Sample holder, test chamber and test bench for carrying out corrosion and / or erosion tests, and method for carrying out corrosion and / or erosion tests using such a sample holder

Abstract

The invention relates to a sample holder capable of being rotated in a test chamber about an axis of rotation (X) in order to carry out corrosion and / or erosion tests, the sample holder having a lateral surface (1) that is rotationally symmetrical about the axis of rotation (X) and on which at least a first support for a first sample and a second support for a second sample are arranged so as to expose a main surface of each sample extending radially with respect to the axis (X) to a visible flow of a particle-fluid mixture, the sample holder comprising means for attaching the first and second samples, the first and second supports being configured such that, when the first and second samples are attached to the first and second supports, respectively, the main surface of each sample is oriented at a respective different angle with respect to a plane perpendicular to the axis (X).

Description

Sample holder, test chamber and test bench for carrying out corrosion and / or erosion tests, and method for carrying out corrosion and / or erosion tests using such a sample holder

[0001] The invention relates to a sample holder adapted to be rotated in a test chamber around an axis of rotation for carrying out corrosion and / or erosion tests, a test chamber comprising this sample holder, a test bench comprising such a test chamber and a method for carrying out corrosion and / or erosion tests using such a sample holder. STATE OF THE ART

[0002] Erosion refers to the progressive wear of a material under the effect of a high-speed flow of fluid and / or solid particles. Corrosion refers to the progressive deterioration of a material caused by a chemical and / or electrochemical reaction with the environment. The corrosion phenomenon is a relatively well-known and predictable process. In contrast, the erosion phenomenon is not as well understood. Attempts to model the latter in very specific cases remain few. The evolution of a material undergoing both corrosion and erosion phenomena is even more difficult to predict and requires the implementation of experimental tests.For example, such a situation of simultaneous corrosion and erosion is frequently encountered inside centrifugal pumps, for example centrifugal pumps used by the chemical, petrochemical or hydrometallurgical industries, and explains their relatively rapid degradation. As another example, this dual phenomenon is encountered in centrifugal pumps in the phosphate mining industries, said pumps being able to circulate mixtures comprising phosphoric acid and phosphogypsum particles.

[0003] Test benches are therefore used to test the resistance of materials (e.g., materials constituting components of the aforementioned centrifugal pumps) to erosion and corrosion simultaneously. The erosive and corrosive conditions created by such test benches accelerate the phenomenon of material degradation and facilitate its observation.

[0004] Slurry pot test benches consist of a test chamber, most often cylindrical in shape, closed by a lid, and a sample holder positioned inside the test chamber. Before starting a test, the experimenter attaches samples of the materials to be tested, which may be cylindrical or rectangular parallelepiped, to the sample holder and fills the chamber with a mixture comprising a liquid that may be corrosive, for example an acid, and erosive particles.

[0005] At the beginning of the test, the sample holder is rotated in the test chamber, so that the samples are exposed to a stream of the liquid-particle mixture. Hard particles erode the exposed sample surfaces under the effect of shocks. The sample rotation speed, the mass ratio of the liquid-particle mixture, the size of the erosive particles, the type of corrosive liquid, the duration of the test and the temperature are all parameters that the experimenter can vary to study their influence.

[0006] At the end of the test, the experimenter recovers the samples which he can analyze, in particular by measuring the loss of mass undergone by said samples or by observing the profilometry of their surface, for example by microscopy.

[0007] However, the corrosive and erosive flows circulating in a centrifugal pump will come into contact with the various components of the pump at various impact angles. The value of the impact angle of the corrosive / erosive flow on said components is an additional parameter that influences the erosion / corrosion phenomenon of the materials constituting said components.

[0008] In a test chamber, the use of samples exposing a main surface to the corrosive / erosive flow only allows for the simulation of a single impact angle per test and therefore requires carrying out as many tests as there are impact angles of interest to obtain a complete study of the erosion / corrosion phenomenon. In addition, when successively carrying out the different tests by varying the impact angle, other parameters may change slightly independently of the experimenter's wishes, which complicates the comparison of the results obtained in these different tests.

[0009] The use of cylindrical samples makes it possible to simulate different impact angles in the same test. However, the eroded / corroded surface at each impact angle is very small. This very small surface area, coupled with the very shape of the samples, makes post-processing of said samples, particularly their analysis by profilometry, difficult. BRIEF DESCRIPTION OF THE INVENTION

[0010] An aim of the invention is to design a sample holder allowing more representative testing of fluid flows and / or solid particles impacting a material, while allowing easy analysis of the samples and good interpretation of the results.

[0011] To this end, the invention proposes a sample holder adapted to be rotated in a test chamber around an axis of rotation for carrying out corrosion and / or erosion tests, the sample holder having a lateral surface of revolution around said axis of rotation and on which are arranged at least a first support for a first sample and a second support for a second sample so as to expose a main surface of each sample extending radially with respect to the axis of rotation to an apparent flow of a particle-fluid mixture, the sample holder further comprising means for fixing the first and second samples respectively on the first and second supports, the sample holder being characterized in that: the first support and the second support are configured so that,when the first sample and the second sample are fixed respectively on the first support and the second support, the main surface of each sample is oriented at a respective different angle with respect to a plane perpendicular to the axis of rotation.,

[0012] The sample holder according to the invention makes it possible to fix two samples in such a way that the impact angle formed between the flow of fluid and / or particles and the main surface of each of the two samples is different between the two samples. Thus, the sample holder according to the invention makes it possible to test, during the same test, two different impact angles, all the other experimental parameters being strictly identical. In addition, the sample holder makes it possible to generate, for each of the impact angles, a complete surface of the sample corroded / eroded according to said impact angle, said surface then being easily analysable, in particular in microscopy experiments.

[0013] According to other optional features of the invention taken alone or in combination when technically possible:

[0014] - the second support is oriented at 180° from the first support relative to the axis of rotation of the sample holder in a plane perpendicular to said axis of rotation;

[0015] - a third support for a third sample and a fourth support for a fourth sample are arranged on the lateral surface of the sample holder so as to expose a main surface of the third sample and the fourth sample extending radially with respect to the axis of rotation to an apparent flow of a particle-fluid mixture, the sample holder further comprising means for fixing the third and fourth samples respectively on the third support and the fourth support, the third support and the fourth support being configured so that, when each of the four samples is fixed on its respective support, the main surface of each of the four samples is oriented at a different respective angle with respect to a plane perpendicular to the axis of rotation;

[0016] - the second support, the third support and the fourth support are oriented respectively at 90°, 180° and 270° from the first support relative to the axis of rotation of the sample holder in a plane perpendicular to said axis of rotation;

[0017] - each holder comprises a groove formed in the lateral surface and adapted to receive a respective sample;

[0018] - each support further comprises a bearing surface parallel to the groove and at least two orifices for the passage of the means for fixing the bearing surface to the groove;

[0019] - the means for fixing each sample comprise at least two polytetrafluoroethylene cylinders and at least two pressure screws, the cylinders and the screws being adapted to be inserted into the orifices of the respective support by the bearing surface of said support, so that, when a sample is fixed on its respective support, each of the polytetrafluoroethylene cylinders is inserted into one of the orifices of the respective support, each of the pressure screws pressing, through one of the orifices, on the cylinder inserted in said orifice, so as to keep the sample fixed on the sample holder without there being any contact between the screws and the sample;

[0020] - the means for fixing each sample comprise at least two headless screws adapted to be inserted into the holes of the respective support through the bearing surface of said support, so that, when a sample is fixed on its respective support, each of the headless screws is inserted into one of the holes of the respective support and keeps the sample fixed on the sample holder by contact with said sample;

[0021] - the sample holder further comprises an upper surface perpendicular to the axis of rotation;

[0022] - each support further comprises a notch which extends in the lateral surface of the upper surface up to the bearing surface, said notch having an edge perpendicular to the bearing surface;

[0023] - the sample holder further comprises a conical-shaped cover configured to fit onto the upper surface of the sample holder perpendicular to the axis of rotation, the top of the cone, when the cover is fitted, being located on the axis of rotation of the sample holder;

[0024] - the sample holder further comprises a lower surface perpendicular to the axis of rotation and in which the volume defined by the upper surface, the lateral surface and the lower surface is full of material.

[0025] The invention also relates to a test chamber suitable for carrying out corrosion and / or erosion tests, comprising a sample holder as previously described arranged to rotate in said chamber.

[0026] According to other optional features of the invention taken alone or in combination when technically possible:

[0027] - the test chamber further comprises a bottom wall, a top wall and at least one side wall extending between the bottom wall and the top wall, the top wall forming a cover of the test chamber, the sample holder being positioned inside the space delimited by the bottom wall, the top wall and the side wall of the test chamber and the axis of rotation of the sample holder being perpendicular to the bottom wall.

[0028] - the test chamber further comprises an inlet supplied with a circulation flow of the particle-fluid mixture and an outlet such that, when carrying out a corrosion and / or erosion test, said circulation flow circulates in the test chamber from the inlet to the outlet through which the circulation flow is discharged, the inlet and the outlet of the test chamber being located respectively in the upper wall and in the lower wall of said chamber, the inlet being located at the intersection between the upper wall and the axis of rotation of the sample holder.

[0029] The invention further relates to a test bench for carrying out corrosion and / or erosion tests comprising a test chamber as previously described.

[0030] The invention finally relates to an erosion / corrosion testing method comprising:- fixing at least two samples on a sample holder as previously described, the sample holder being positioned in a test chamber also as previously described,

[0031] - rotating the sample holder inside the test chamber by exposing a main surface of each of the at least two samples to an apparent flow of a particle-fluid mixture, so as to erode and / or corrode each of said surfaces,

[0032] - analysis of the main surface of each of the at least two samples BRIEF DESCRIPTION OF THE FIGURES

[0033] Other characteristics and advantages of the invention will emerge from the detailed description which follows, with reference to the appended drawings, in which:

[0034] - figures 1A and 1B represent two viewing angles of an embodiment of the sample holder according to the invention adapted for fixing four samples,

[0035] - Figures 2A and 2B represent an embodiment of the sample holder according to the invention adapted for fixing four samples, the sample holder comprising a conical-shaped cover, corresponding to a view in which the four samples are fixed on the sample holder and the cover fitted onto the upper surface of the sample holder, corresponding to an exploded view of the same sample holder, cover and four samples,

[0036] - represents an embodiment of the means for fixing a sample included in the sample holder of the invention,

[0037] - Figure 4 represents a test bench comprising a test chamber and a sample holder according to the invention.

[0038] For readability reasons, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION OF EMBODIMENTS

[0039] The invention relates to a sample holder suitable for carrying out corrosion and / or erosion tests on materials to be tested. For this purpose, said sample holder is suitable for fixing at least two samples of said materials to be tested. Furthermore, it is suitable for being rotated on itself in a test chamber, said test chamber being filled with a particle-fluid mixture comprising erosive particles and / or a corrosive fluid.

[0040] The rotation on itself of the sample holder immersed in the particle-fluid mixture on which the samples of the material to be tested have been previously fixed makes it possible to subject each of the samples fixed on the sample holder to an apparent flow of the particle-fluid mixture having an erosive and / or corrosive action which mimics the operating conditions of centrifugal pumps in the chemical, metallurgical and / or mining industries. Thus, if the sample holder rotates on itself at a given rotation speed, the samples are struck by an apparent flow of the particle-fluid mixture which is oriented tangentially with respect to the axis of rotation of the sample holder. In addition, the speed of said flow is the tangential speed of the sample, this tangential speed being directly related to the rotation speed of the sample holder.

[0041] Before and after the test, the samples can be analyzed (for example by profilometry and / or by mass loss) so as to classify the materials constituting said samples according to their resistance to corrosion and / or erosion under the simulated conditions and thus determine which of the materials is most suitable for the operating conditions of the centrifugal pump.

[0042] Furthermore, the sample holder can be used to study erosive and / or corrosive damage modes and thus allow the experimenter to model said damage modes and guide the process of developing new materials.

[0043] In the following, an embodiment of the sample holder according to the invention is described more particularly in which the sample holder is adapted to fix four samples of the materials to be tested. Such an embodiment of the sample holder is shown in Figures 1A to 3.

[0044] The sample holder according to the invention has a lateral surface of revolution 1 around an axis of rotation (X). The sample holder may further comprise an upper surface 2 perpendicular to the axis of rotation (X). Finally, the sample holder may also comprise a lower surface 3 perpendicular to the axis of rotation (X), such that the interior volume defined by the upper surface 2, the lateral surface 1 and the lower surface 3 is full of material. Advantageously, the sample holder is full of material and therefore cannot be penetrated by the particles and / or the fluid; thus, the sample holder makes it possible not to generate parasitic flows of the particle-fluid mixture inside the sample holder when said sample holder is rotating around its axis of rotation (X) in the test chamber, immersed in the particle-fluid mixture.Indeed, such parasitic flows in the center of the chamber inside the sample holder are not representative of the interior of a centrifugal pump and could distort the measurement results. While the positioning of baffles on the walls of the test chamber including the rotating sample holder partially reduces such parasitic flows, the use of a solid sample holder reduces said flows even more significantly.

[0045] A first support, a second support, a third support and a fourth support are arranged on the lateral surface 1 to respectively accommodate a first sample, a second sample, a third sample and a fourth sample. Preferably, the supports are arranged regularly on the sample holder, in particular with an identical distance between adjacent supports on the circumference of the sample holder. For example, the second support, the third support and the fourth support are oriented respectively at 90°, 180° and 270° from the first support relative to the axis of rotation (X) of the sample holder in a plane perpendicular to said axis of rotation.Such a distribution of the four supports on the lateral surface 1 of the sample holder advantageously allows for good balancing of the sample holder when said sample holder, on which the four samples have been previously fixed, is rotating around its axis of rotation (X).

[0046] The four supports provided on the lateral surface 1 of the sample holder are arranged such that, when each of the four samples is fixed on its respective support, a main surface of each of the four samples is oriented at a respective angle relative to a plane perpendicular to the axis of rotation (X) different from the respective angle of the other three samples. Alternatively, two or three samples out of the four samples may be oriented at the same respective angle when fixed on the sample holder without departing from the scope of the present invention.

[0047] For example, the main surfaces of the first, second, third and fourth samples may be oriented at respective angles of 10°, 30°, 45° and 90° relative to the plane perpendicular to the axis of rotation (X). In other words, when the sample holder is rotating about the axis (X) in the particle-fluid mixture, the main surfaces of the first, second, third and fourth samples are struck by an apparent flow of said particle-fluid mixture at respective impact angles of 10°, 30°, 45° and 90°, where the impact angle is the angle between the direction of the apparent flow and the plane defined by the main surface. 90° therefore corresponds to an impact of the apparent flow along the normal of the main surface while 10° corresponds to a much more grazing impact of the apparent flow.

[0048] Thus, the sample holder advantageously makes it possible to test, during the same test, up to four different impact angles of the apparent flow of the particle-fluid mixture exhibiting a corrosive and / or erosive action, all the other experimental parameters being strictly identical (in particular the temperature, the mass ratio between particles and fluid, the nature of the particles and the fluid, etc.). Even more advantageously, the sample holder makes it possible to test four different impact angles on the same material to be tested if the four samples are made of the same said material.

[0049] The sample holder also makes it possible to generate, for each of the impact angles, a complete surface of the sample corroded / eroded according to said impact angle, and therefore damage to said surface which is well representative of the impact angle studied. Said surface is then easily analyzed, particularly in microscopy experiments.

[0050] The sample holder further comprises means for fixing the first sample, the second sample, the third sample and the fourth sample respectively on the first, second, third and fourth supports.

[0051] In a particular embodiment of the first, second, third and fourth supports shown in Figures 1 and 2, each of said supports may comprise a groove 4a, 4b, 4c, 4d formed in the lateral surface 1 and adapted to receive a respective sample 5a, 5b, 5c, 5d. In other words, the shape of each groove 4a, 4b, 4c, 4d is adapted to allow the insertion of the respective sample 5a, 5b, 5c, 5d into said groove 4a, 4b, 4c, 4d.

[0052] For example, samples 5a, 5b, 5c, 5d having a parallelepiped shape and dimensions of the order of 30 mm x 30 mm x 10 mm can be used, each groove 4a, 4b, 4c, 4d of the sample holder then forming an opening on the lateral surface 1 of the sample holder with dimensions 30 mm x 10 mm allowing the insertion of the respective sample 5a, 5b, 5c, 5d by one of its four faces with dimensions 30 mm x 10 mm. The depth of each groove can for example be between 1 mm and 3 mm depending on the size of the samples.

[0053] The grooves 4a, 4b, 4c, 4d are oriented at respective angles relative to a plane perpendicular to the axis of rotation (X) different from each other and equal to the impact angles that one wishes to study, for example 10°, 30°, 45° and 90°. When the samples 5a, 5b, 5c and 5d are inserted into their respective groove 4a, 4b, 4c, 4d, the main surface of each sample 5a, 5b, 5c, 5d is oriented at a respective angle relative to said plane which is that of the orientation of the groove 4a, 4b, 4c, 4d of said sample 5a, 5b, 5c, 5d (according to the length and not the width of said groove).

[0054] In the example in which the samples 5a, 5b, 5c, 5d are parallelepipedal in shape and have dimensions of 30 mm x 30 mm x 10 mm and in which said samples are inserted into their respective groove 4a, 4b, 4c, 4d by a face of dimension 30 mm x 10 mm, the main surface of each sample is the face of dimension 30 mm x 30 mm of said sample facing the apparent flow of the particle-fluid mixture when the sample holder is rotating around the axis of rotation (X) according to an impact angle defined by the orientation of its respective groove 4a, 4b, 4c, 4d.

[0055] Each support may further comprise a bearing surface 6a, 6b, 6c, 6d parallel to the groove 4a, 4b, 4c, 4d and at least two orifices 7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2 for the passage of the means for fixing the bearing surface 6a, 6b, 6c, 6d to the groove 4a, 4b, 4c, 4d.

[0056] According to a variant of the fixing means shown in the, said fixing means of each sample may comprise at least two cylinders 8 made of polytetrafluoroethylene, polyamide or any other material having particular resistance to corrosion, and at least two pressure screws 9, preferably metal screws, for example screws made of 304L stainless steel or 316L stainless steel. The metal screws advantageously have a resistance to centrifugal forces greater than non-metallic screws.The cylinders 8 and the screws 9 are adapted to be inserted into the holes 7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2 of the respective support by the bearing surface 6a, 6b, 6c, 6d of said support, so that, when a sample 5a, 5b, 5c, 5d is fixed on its respective support, each of the cylinders 8 is inserted into one of the holes 7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2 of the respective support, each of the pressure screws 9 pressing, through one of the holes 7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2, on the inserted cylinder 8 in said orifice 7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2, so as to keep the sample 5a, 5b, 5c, 5d fixed on the sample holder without there being any contact between the screws 9 and the sample 5a, 5b, 5c, 5d.

[0057] Interposing cylinders made of polymers or any other material with good corrosion resistance between the pressure screws and the samples advantageously makes it possible, when the sample is metallic, to avoid metal-metal contact which could be the site of galvanic corrosion in the presence of a corrosive fluid which can act as an aggressive electrolyte, for example a 3.5% by mass saline water solution or an acid solution including, but not limited to, sulfuric acid, nitric acid and / or hydrochloric acid.

[0058] According to another variant (not shown) of the fixing means, said means for fixing each sample comprise at least two headless screws adapted to be inserted into the orifices 7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2 of the respective support by the bearing surface 6a, 6b, 6c, 6d of said support, so that, when a sample 5a, 5b, 5c, 5d is fixed on its respective support, each of the headless screws is inserted into one of the orifices 7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2 of the respective support and keeps the sample fixed on the sample holder by contact with said sample. Headless screws are preferably made of stainless steel type 304L, 316L or 904L or any other material with particular resistance to corrosion.

[0059] Each sample 5a, 5b, 5c, 5d may further comprise two bores configured so that, when the sample 5a, 5b, 5c, 5d is fixed on its respective support, the cylinders 8 or the headless screws inserted into the holes 7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2 by the bearing surface 6a, 6b, 6c, 6d of said support, are further inserted into said bores. Such a configuration ensures firm holding of each sample on its respective support, even at high rotation speeds of the sample holder, for example speeds between 10 m / s and 25 m / s.

[0060] In the case where the sample holder comprises an upper surface 2, each support may also comprise a notch 10a, 10b, 10c, 10d which extends in the lateral surface 1 of the upper surface 2 up to the bearing surface 6a, 6b, 6c, 6d, said notch 10a, 10b, 10c, 10d having an edge perpendicular to the bearing surface. The notches 10a, 10b, 10c, 10d allow easy access to the bearing surface 6a, 6b, 6c, 6d for the insertion of the fixing means 8, 9.

[0061] Advantageously, the sample holder may further comprise a conical-shaped cover 11 configured to fit onto the upper surface 2 of the sample holder perpendicular to the axis of rotation (X), the apex of the cone, when the cover 11 is fitted, being located on the axis of rotation (X) of the sample holder.

[0062] In other alternative embodiments not developed in the present description, the sample holder may be adapted for fixing a number of samples greater than or equal to two and different from four, and for this purpose comprises a number of suitable supports. Said supports are configured so that, when the different samples are fixed on their respective supports, the main surface of a first sample is oriented at a respective angle relative to a plane perpendicular to the axis of rotation of the sample holder different from the respective angle of another sample. In other words, the sample holder makes it possible to test at least two different impact angles.In a particular embodiment, the sample holder allows testing as many impact angles as it has sample supports, the main surface of each sample being oriented at a respective angle relative to the plane perpendicular to the axis of rotation of the sample holder different from the respective angles of all the other samples.

[0063] In the case where the sample holder is suitable for fixing two samples, the second support is preferably oriented at 180° from the first support relative to the axis of rotation of the sample holder in a plane perpendicular to said axis of rotation. In the case where the sample holder is suitable for fixing three samples, the second support and the third support are preferably oriented respectively at 60° and 120° from the first support relative to the axis of rotation of the sample holder in a plane perpendicular to said axis of rotation. Such a distribution of the supports in the case where the support comprises two to four supports makes it possible to ensure good balance of the sample holder around its axis of rotation and can be easily adapted by a person skilled in the art regardless of the number of supports.

[0064] Finally, all the characteristics of the sample holder and its supports as previously described in the case where said sample holder comprises four supports can be applied to a sample holder comprising a different number of supports without departing from the scope of the present invention.

[0065] The invention extends to a test chamber comprising a sample holder produced according to any one of the embodiments previously described, the test chamber being configured so that, when carrying out corrosion and / or erosion resistance tests, the sample holder and the samples fixed on the sample holder can be immersed in a particle-fluid mixture comprising erosive particles and / or a corrosive fluid and the sample holder can be rotated on itself around its axis of rotation (X). The rotation of the sample holder on itself along the axis of rotation (X) in the particle-fluid mixture subjects the samples to the impact of an apparent flow of said particle-fluid mixture, said flow having a corrosive and / or erosive action on said samples.

[0066] According to a particularly advantageous embodiment of the test chamber 21, illustrated in FIG. 4, the test chamber 21 may comprise an inlet 23 supplied by a circulation flow of the particle-fluid mixture 22 and an outlet 24 through which said flow is drained. During a corrosion and / or erosion test, the circulation flow of the particle-fluid mixture 22 therefore circulates from the inlet 23 of the test chamber to the outlet 24 of said chamber 21. Optionally, the test chamber 21 may further comprise a first valve adapted to control the flow rate of the circulation flow of the particle-fluid mixture 22 entering the test chamber 21 and a second valve adapted to control the flow rate of the circulation flow of the particle-fluid mixture 22 leaving the test chamber 21, so as to keep the level of the particle-fluid mixture 22 constant in the test chamber 21 throughout the duration of the test.The level of the particle-fluid mixture 22 in the test chamber 21 is chosen so as to keep the sample holder 20 completely submerged.

[0067] The rotation speed of the sample holder 20 is large compared to the speed of the circulation flow of the particle-fluid mixture 22 through the test chamber 21, so that the speed of the apparent flow of the particle-fluid mixture 22 impacting the samples 5a, 5b, 5c, 5d is generally that of the rotation speed of the sample holder 20 (without impact of the circulation flow of the particle-fluid mixture 22 through the test chamber 21).

[0068] Such an embodiment of the test chamber 21 advantageously makes it possible to drain the erosive particles used to carry out the test and to constantly supply the test chamber 21 with new erosive particles, so that the erosive action of the particles does not vary during the test and is well controlled by the experimenter. Such an embodiment of the test chamber 21 also makes it possible to obtain a more fluid and more homogeneous distribution of the particle-fluid mixture in all areas of the test chamber. In particular, even if the erosive particles used are very massive, they have less tendency to fall to the bottom of the test chamber 21 under the effect of gravity during the test.

[0069] According to another embodiment (not shown) of the test chamber, the test chamber may be similar to a pot comprising neither an inlet that can be supplied by a circulation flow of the particle-fluid mixture during a test, nor an outlet for draining said circulation flow, so that the test chamber must be filled with the particle-fluid mixture, so as to immerse the sample holder and the samples, by the experimenter prior to carrying out the test.

[0070] Geometrically, the test chamber 21 may comprise a bottom wall 25, a top wall 26 and at least one side wall 27 which extends between the bottom wall 25 and the top wall 26. The bottom wall 25, the side wall 27 and the top wall 26 then define an interior space of the test chamber 21, so that the sample holder 20 is positioned inside this space. Furthermore, during a test, it is this space which is filled with the particle-fluid mixture 22.

[0071] The axis of rotation (X) of the sample holder 20 is for example placed perpendicular to the lower wall 25 of the test chamber 21. Thus, if the sample holder 20 comprises a lower surface 3, the lower surface 3 is positioned parallel opposite the lower wall 25 of the test chamber 21. If the sample holder 20 comprises an upper surface 2, the upper surface 2 is positioned parallel opposite the upper wall 26 of the test chamber 21.

[0072] The upper wall 26 of the test chamber 21 may form a cover. In this way, the cover may be removed, for example to position the samples 5a, 5b, 5c, 5d and / or the sample holder 20 in the test chamber 21 before the start of the implementation of an erosion and / or corrosion test or to remove them at the end of the test. If the test chamber 21 does not include an inlet and outlet for a circulation flow of the particle-fluid mixture 22, the cover may also be removed to fill said test chamber 21 with said mixture 22 prior to the implementation of the test. Conversely, the cover of the test chamber 21 may be fitted onto the side wall 27, so as to close the test chamber 21 during the implementation of the corrosion and / or erosion test.

[0073] If the test chamber 21 has an inlet 23 and an outlet 24, the sample holder 20 advantageously comprises a conical-shaped cover as previously described and the inlet of the test chamber 3 is preferably located in the upper wall 26 of the test chamber 21, at the intersection between said upper wall 26 and the axis of rotation (X) of the sample holder 20. In this way, the particle-fluid mixture 22 is introduced directly into the center of the upper cone of the sample holder 20, which makes it possible, in the case of large / heavy particles, to distribute said particles uniformly in the test chamber 21.

[0074] The outlet 24 of the test chamber 21 can be formed in the lower wall 25 of the test chamber 21.

[0075] The invention also extends to a test bench for carrying out corrosion and / or erosion tests comprising a test chamber 21 according to any one of the embodiments previously described.

[0076] For example, in the case where the test chamber comprises an inlet 23 and an outlet 24 for the circulation of a circulation flow of a particle-fluid mixture 22 through said test chamber 21, the test bench may further comprise a mixing reactor 28 supplied with new erosive particles 29 and a corrosive fluid, the mixing reactor 28 being configured to mix the new erosive particles 29 and the corrosive fluid, so as to obtain, at the outlet of the mixing reactor 28, the circulation flow of the particle-fluid mixture 22 which supplies the inlet 23 of the test chamber 21. The mixing reactor is optionally equipped with a heating system 30.

[0077] The test bench may also comprise: - a decantation system 31 in fluid connection with the outlet 24 of the test chamber 21, the decantation system 31 being configured to decant the particle-fluid mixture 22 from the test chamber 21 so as to separate the erosive particles used to carry out the test and the corrosive fluid from said mixture 22, - a fluid recycling network 32 configured to convey the corrosive fluid separated from the erosive particles used to carry out the test from the decantation system 31 to the mixing reactor 28, so that the corrosive fluid is recycled, while the erosive particles used to carry out the test are systematically eliminated.

[0078] The invention finally relates to an erosion / corrosion testing method.

[0079] The testing method comprises securing the samples to be tested on a sample holder according to any one of the embodiments of the sample holder previously described, the sample holder being positioned in a test chamber according to any one of the embodiments of said test chamber previously described. If the test chamber comprises a cover, the cover is opened, so as to allow the securing of said samples.

[0080] If the test chamber is a pot, the method further comprises filling the test chamber with a mixture of erosive particles and corrosive fluid, such that the samples and the sample holder are immersed in the mixture.

[0081] Alternatively, if the test chamber comprises an inlet and an outlet allowing the circulation of a flow of the particle-fluid mixture, the method may comprise a step of filling a reservoir of particles and / or a reservoir of corrosive fluid external to the test chamber.

[0082] The method further comprises rotating the sample holder within the test chamber. As previously described, rotating the sample holder exposes a major surface of each of the samples to a flow of fluid and / or solid particles, so as to erode and / or corrode each of said surfaces according to at least two different impact angles.

[0083] The method finally comprises stopping the rotation of the sample holder, removing the fixing means so as to recover the samples and analyzing the main surface of each of said samples.

Claims

Sample holder adapted to be rotated in a test chamber around an axis of rotation (X) for carrying out corrosion and / or erosion tests, the sample holder having a lateral surface (1) of revolution around said axis of rotation (X) and on which are arranged at least a first support for a first sample and a second support for a second sample so as to expose a main surface of each sample extending radially with respect to the axis of rotation (X) to an apparent flow of a particle-fluid mixture, the sample holder further comprising means for fixing the first and second samples respectively on the first and second supports, the sample holder being characterized in that: the first support and the second support are configured so that, when the first sample and the second samples are fixed respectively on the first support and the second support,the main surface of each sample is oriented at a different respective angle relative to a plane perpendicular to the axis of rotation (X)., Sample holder according to claim 1, wherein the second support is oriented at 180° from the first support relative to the axis of rotation (X) of the sample holder in a plane perpendicular to said axis of rotation (X). The sample holder of claim 1, wherein a third support for a third sample and a fourth support for a fourth sample are provided on the lateral surface of the sample holder so as to expose a main surface of the third sample and the fourth sample extending radially with respect to the axis of rotation (X) to an apparent flow of a particle-fluid mixture, the sample holder further comprising means for fixing the third and fourth samples respectively on the third support and the fourth support, the third support and the fourth support being configured so that, when each of the four samples is fixed on its respective support, the main surface of each of the four samples is oriented at a different respective angle with respect to a plane perpendicular to the axis of rotation (X). Sample holder according to claim 3, wherein the second support, the third support and the fourth support are oriented respectively at 90°, 180° and 270° from the first support relative to the axis of rotation (X) of the sample holder in a plane perpendicular to said axis of rotation (X). Sample holder according to one of claims 1 to 4, wherein each holder comprises a groove (4a, 4b, 4c, 4d) formed in the lateral surface (1) and adapted to receive a respective sample (5a, 5b, 5c, 5d). Sample holder according to claim 5, wherein each support further comprises a bearing surface (6a, 6b, 6c, 6d) parallel to the groove (4a, 4b, 4c, 4d) and at least two orifices (7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2) for the passage of the means for fixing the bearing surface (6a, 6b, 6c, 6d) to the groove (4a, 4b, 4c, 4d). Sample holder according to claim 6, wherein the means for fixing each sample comprise at least two polytetrafluoroethylene cylinders (8) and at least two pressure screws (9), the cylinders (8) and the screws (9) being adapted to be inserted into the orifices (7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2) of the respective support by the bearing surface (6a, 6b, 6c, 6d) of said support, so that, when a sample (5a, 5b, 5c, 5d) is fixed on its respective support, each of the polytetrafluoroethylene cylinders (8) is inserted into one of the orifices (7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2) of the respective support, each of the pressure screws (9) forming pressure, through one of the orifices (7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2), on the cylinder (8) inserted in said orifice (7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2), so as to maintain the sample (5a, 5b, 5c,5d) fixed on the sample holder without there being any contact between the screws (9) and the sample (5a, 5b, 5c, 5d)., Sample holder according to claim 6, wherein the means for fixing each sample (5a, 5b, 5c, 5d) comprise at least two headless screws adapted to be inserted into the holes (7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2) of the respective support by the bearing surface (6a, 6b, 6c, 6d) of said support, so that, when a sample (5a, 5b, 5c, 5d) is fixed on its respective support, each of the headless screws is inserted into one of the holes (7a1, 7a2, 7b1, 7b2, 7c1, 7c2, 7d1, 7d2) of the respective support and keeps the sample (5a, 5b, 5c, 5d) fixed on the sample holder by contact with said sample (5a, 5b, 5c, 5d). Sample holder according to one of claims 1 to 8, further comprising an upper surface (2) perpendicular to the axis of rotation (X). Sample holder according to claim 9 in combination with one of claims 6 to 8, wherein each support further comprises a notch (10a, 10b, 10c, 10d) which extends in the lateral surface (1) of the upper surface (2) up to the bearing surface (6a, 6b, 6c, 6d), said notch (10a, 10b, 10c, 10d) having an edge perpendicular to the bearing surface (6a, 6b, 6c, 6d). Sample holder according to one of claims 9 or 10, wherein the sample holder further comprises a conical shaped cover (11) configured to fit onto the upper surface (2) of the sample holder perpendicular to the axis of rotation (X), the apex of the cone, when the cover (11) is fitted, being located on the axis of rotation (X) of the sample holder. Sample holder according to one of claims 9 to 11, further comprising a lower surface (3) perpendicular to the axis of rotation (X) and in which the volume defined by the upper surface (2), the lateral surface (1) and the lower surface (3) is full of material. Test chamber suitable for carrying out corrosion and / or erosion tests, comprising a sample holder according to one of claims 1 to 12 arranged to rotate in said chamber. The test chamber of claim 13, further comprising a bottom wall (25), a top wall (26) and at least one side wall (27) extending between the bottom wall (25) and the top wall (26), the top wall (26) forming a cover of the test chamber, the sample holder being positioned within the space defined by the bottom wall (25), the top wall (26) and the side wall (27) of the test chamber and the axis of rotation (X) of the sample holder being perpendicular to the bottom wall (25). Test chamber (21) according to claim 14, further comprising an inlet (23) supplied with a circulation flow of the particle-fluid mixture and an outlet (24) so ​​that, when carrying out a corrosion and / or erosion test, said circulation flow circulates in the test chamber (21) from the inlet (23) to the outlet (24) through which the circulation flow is discharged, the inlet (23) and the outlet (24) of the test chamber (21) being located respectively in the upper wall (26) and in the lower wall (25) of said chamber (21), the inlet (23) being located at the intersection between the upper wall (26) and the axis of rotation (X) of the sample holder. Test bench for carrying out corrosion and / or erosion tests comprising a test chamber according to one of claims 13 to 15. An erosion / corrosion testing method comprising:- fixing at least two samples on a sample holder according to one of claims 1 to 12, the sample holder being positioned in a test chamber according to one of claims 13 to 15,- rotating the sample holder inside the test chamber by exposing a main surface of each of the at least two samples to an apparent flow of a particle-fluid mixture, so as to erode and / or corrode each of said surfaces,- analyzing the main surface of each of the at least two samples.

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