232 results about "Mass content" patented technology

The invention discloses a method for recovering high-quality germanium concentrate from scrapped glass optical fibers, and belongs to the technical field of rare metal recovery. Crushing and screening the scrapped glass optical fiber to obtain optical fiber powder; the optical fiber powder and NaOH or Na2CO3 are uniformly mixed, the molar ratio of NaSi to NaGe of the mixture is (3-6): 1, and roasting is conducted for 2-4 h at the temperature of 500-800 DEG C; mixing the roasted material with water according to a solid-to-liquid ratio of 1: (4-10), heating to 50-100 DEG C, stirring and dissolving to generate a leaching solution; after filtering, feeding the filtered clear liquid into a spraying device filled with adsorption resin from an inlet of the device at the temperature of 5-40 DEG C and the flow speed of 5-50mm / min; and feeding an inorganic acid desorption agent into a spraying device from an outlet of the device at the temperature of 50-80 DEG C and the flow speed of 10-100mm / min, collecting the desorbed liquid, and adding water which is 3-5 times of the theoretical hydrolysis amount to obtain the germanium concentrate. The method is simple in technological process, low in energy consumption and high in metal direct recovery rate, the germanium mass content of the enriched germanium concentrate is larger than 40%, the germanium recovery rate is larger than 92%, the main component obtained after germanium recovery is sodium silicate, and multiple benefits of resources, economy, environment and the like are achieved.

The invention relates to the technical field of preparation of silicon carbide ceramics, in particular to an in-situ reaction sintered silicon carbide ceramic and a preparation method thereof.The preparation method comprises the following technological stages which are conducted in sequence: S1, preparation of silicon carbide slurry, specifically, organic matter precursor raw materials are weighed according to the mass content percentage to form the silicon carbide slurry; s2, vacuum grouting: injecting the silicon carbide slurry in the vacuum grouting tank into the shaping mold from the bottom of the shaping mold to form a silicon carbide green body; and S3, in-situ reaction sintering is conducted, specifically, the silicon carbide green body is placed in a sintering furnace, heating, heat preservation and cooling are conducted on the silicon carbide green body in the argon atmosphere through a segmented temperature control technology, and the silicon carbide ceramic is obtained. The silicon carbide ceramic prepared by the method disclosed by the invention has relatively high density and excellent mechanical properties.

The invention relates to the technical field of water-soluble fertilizers, in particular to a high-magnesium medium-trace particle water-soluble fertilizer and a preparation method thereof. The invention discloses a high-magnesium medium-trace particle water-soluble fertilizer, which is prepared by carrying out spray granulation on granulation slurry in a granulator through a nozzle, the specific gravity of the granulation slurry is greater than or equal to 1.68 g / cm < 3 >, and the mass content of magnesium in the granulation slurry is greater than or equal to 2.0%; in the high-magnesium medium-trace particle water-soluble fertilizer, the mass content of magnesium is greater than or equal to 1.0%. Through the steps of neutralization treatment and filtration impurity removal, free acid and impurities which influence the product quality are effectively removed; by accurately controlling concentration and cooling conditions, the content of free water in the product is reduced, and the physical property of the product is improved; through granulation, the final product has better appearance roundness and stability.

The invention relates to the technical field of alloys, in particular to titanium alloy powder for selective laser melting and a preparation method and application of the titanium alloy powder. The content of V is 3.5%-4.5%; the content of Cr is 1.5%-2.5%; the content of Fe is 0.8%-1.5%; the content of Cu is 0.5%-1%; the content of B is 0.5%-1%; the content of other impurity elements is less than or equal to 0.35%; and the balance of Ti. The mass content ratio of Al to V is (1.3-1.5): 1; the mass content ratio of Cr to Fe is (2-3): 1. The titanium alloy powder is applied to preparation of titanium alloy parts through selective laser melting. The titanium alloy powder is low in cost and simple in preparation process, a titanium alloy part prepared from the titanium alloy powder has high strength and good plasticity at the same time, and the titanium alloy powder is suitable for industrial application.

The invention provides bio-based succinic acid as well as a preparation method and application thereof. The bio-based succinic acid comprises succinic acid, an N element, an S element and a P element, in the bio-based succinic acid, the mass content of an element N is 0.1-10 ppm, the mass content of an element S is 0.1-3 ppm, and the mass content of an element P is 0.1-10 ppm. The bio-based succinic acid provided by the invention contains N, S and P elements with specific contents, and the succinic acid is high in purity and low in impurity content. The bio-based succinic acid is applied to synthesis of chemical products such as polyester, 1, 4-butanediol, succinic anhydride, gamma-butyrolactone and tetrahydrofuran, side reactions can be effectively inhibited, target products with high yield and high purity are obtained, and the products have better hue and physical properties.

A method for inverting true mass content of water ice in lunar soil using a lunar soil water molecule analyzer (LSWMA) includes: obtaining weight data of a lunar soil sample, temperature data of a sample receiving container that receives the lunar soil sample, and duration of a transfer process of the lunar soil sample; obtaining measurement data of total pressure of the water vapor; calculating a sublimation loss based on a sublimation rate and the duration of the transfer process, and estimating a relative sublimation loss rate; correcting the measurement data of the total pressure of the water and obtaining true pressure data of the water vapor; and calculating, based on the true pressure data of the water vapor, mass of the water vapor, and further calculating mass content of water ice in lunar soil.

This invention relates to the field of iron and steel smelting technology, and proposes a method for improving the sintering uniformity of sintering mixtures. The method includes: preparing a first mixture for laying on the lower layer of a sintering machine trolley, and a second mixture for laying on the upper layer thereon, wherein the mass percentage of the first mixture is higher than that of the second mixture, the mass content of fixed carbon in the first mixture is lower than that in the second mixture, and the mass percentage of limestone in the flux used in the first mixture is higher than that in the second mixture; the first mixture is firstly distributed at the head of the sintering machine, and then the second mixture is secondly distributed at the head of the sintering machine; after the distribution is completed, sintering is performed by suction ignition. This invention improves the uniformity of strength and yield between the upper and lower layers of sintered ore, and increases sintering production efficiency.

The present invention discloses a hydrocracking method for producing chemical raw materials. The method includes: (1) in the presence of hydrogen, a hydrocarbon oil raw material enters a first hydrocracking reaction zone to selectively crack the n-alkanes in the hydrocarbon oil raw material to obtain a first hydrocracking product; wherein, in the first hydrocracking product, the mass content of C7 + n-alkanes is controlled below 5.0%; (2) in the presence of hydrogen, the first hydrocracking product enters a second hydrocracking reaction zone to obtain a second hydrocracking product containing monocyclic cyclic hydrocarbons; (3) the second hydrocracking product is separated and fractionated to obtain a gas fraction, light naphtha, and heavy naphtha. When using the hydrocarbon oil as a raw material to produce chemical raw materials, this method can significantly improve the yield and quality of chemical raw materials.

The application provides a method for detecting the content of sodium hypochlorite in chicken, and belongs to the technical field of quantitative detection. Terahertz spectrum testing is performed on a dried chicken sample to obtain the peak height of a sodium hypochlorite characteristic peak; then, according to a standard curve and the peak height of the sodium hypochlorite characteristic peak, the content of sodium hypochlorite in the chicken is obtained; the frequency of the sodium hypochlorite characteristic peak is 1.10 THz or 1.25 THz; and the standard curve is a fitting curve of the mass content of sodium hypochlorite in the chicken and the peak height of the sodium hypochlorite characteristic peak. Different molecules exhibit different absorption peaks in terahertz absorption spectrum, and the application detects the content of sodium hypochlorite in chicken by using a terahertz spectrum method, and obtains the content of sodium hypochlorite in chicken by using the fitting relationship between the peak height of the sodium hypochlorite absorption peak and the content of sodium hypochlorite. The method provided by the application is simple, and can quickly and accurately obtain the content of sodium hypochlorite in chicken.

This invention relates to the field of catalytic cracking catalyst preparation, and discloses a catalytic cracking catalyst, its preparation method, and its application. The catalytic cracking catalyst comprises a molecular sieve, a binder, and clay; based on the total mass of the catalyst, the mass content of the molecular sieve is 60-85%, the mass content of the clay is 5-20%, and the mass content of the binder is 10-35%; the mesopore size of the catalyst is 3-50 nm; in the catalyst, the volume of mesopores with a pore size of 6-10 nm accounts for 8-30% of the total mesopore volume; in the catalyst, the volume of mesopores with a pore size of 30-35 nm accounts for 10-30% of the total mesopore volume. This catalyst exhibits excellent catalytic performance and, when applied to catalytic cracking reactions, especially naphtha catalytic cracking reactions, demonstrates high conversion rates and low-carbon olefin yields.

The invention relates to a composite material as well as a preparation method and application thereof, and belongs to the technical field of compositions of high-molecular compounds. The composite material provided by the invention comprises the following components in parts by weight: 10-70 parts of MS resin, 30-90 parts of SBC resin and 5-20 parts of AS resin, the mass content of methyl methacrylate in the MS resin is 20%-30%. The composite material has good bending resistance and can maintain relatively high transparency after being bent.

The present application relates to the technical field of solid lubricant, and particularly relates to a lubricant particle, which comprises a solid lubricant and a binder, the solid lubricant comprises natural graphite, molybdenum disulfide, hexagonal boron nitride and silicon dioxide; the mass content of the natural graphite is 5% to 20% based on the total mass of the solid lubricant, the mass content of the molybdenum disulfide is 5% to 20%, the mass content of the hexagonal boron nitride is 5% to 20%, and the mass content of the silicon dioxide is 40% to 85%. The lubricant particle of the present application can replace the existing powder solid lubricant to solve the problem that the powder solid lubricant is added into the metal binder, is dispersed and distributed in the carcass, hinders the combination of metal elements, and the lubricants are connected and bridged, further hindering the combination of metal elements.

The invention provides a method for determining the floating content of a binder of a negative plate and application. The method comprises the following steps: acquiring a first weight loss ratio a0 of a negative electrode material at a first position of the negative plate in a target temperature interval; adding the negative electrode material at the first position into a target solvent for reflux, and then filtering and drying to obtain a solid substance; obtaining a second weight loss ratio a1 of the solid substance in the target temperature interval; obtaining a third weight loss ratio x1 of the binder standard substance and a fourth weight loss ratio x3 of the thickener standard substance; obtaining a first actual mass content of the binder based on a0, a1, x1 and x3; and obtaining the floating content of the binder based on the first actual mass content and the designed mass content of the binder. According to the method for determining the floating content of the binder in the negative electrode plate, the actual content of the binder in the negative electrode material at any position in the negative electrode plate can be quantitatively analyzed, and then the floating content of the binder is obtained by combining the design content of the binder.

The present application belongs to the technical field of tribology, and provides a kind of lubricating oil system and its preparation method and application, oil-based super-slippery system.The lubricating oil system provided by the present application includes base oil and oil-soluble copper-based nanoparticle;The mass content of oil-soluble copper-based nanoparticle in the lubricating oil system is 0.01-5.0%.The oil-soluble copper-based nanoparticle in the lubricating oil system provided by the present application can improve the load capacity and anti-wear and friction-reducing performance of base oil as an additive;At the same time, under the action of frictional shear, the oil-soluble copper-based nanoparticle in the lubricating oil system provided by the present application can play a role in friction catalysis, promote the formation of high-performance carbon-based material, i.e., "the third body", in the friction interface and lubricating oil, thereby reducing the friction coefficient between polymer-metal pair to 10 ‑3 order of magnitude, and super-slippery phenomenon occurs, and the wear rate is at 10 ‑8 -10 ‑9 mm 3 / Nm level, reaching near-zero wear state.

The invention relates to the technical field of composite materials, and discloses a composition and a preparation method and application thereof, the composition comprises resin, conductive carbon black, a first antioxidant, a second antioxidant and a cross-linking agent; wherein the mass content of metal elements in the conductive carbon black is not more than 10 ppm; wherein the first antioxidant is 2, 4, 6-tri (3 ', 5'-di-tert-butyl-4 '-hydroxybenzyl) mesitylene and / or 1, 3, 5-tri (3, 5-di-tert-butyl-4'-hydroxybenzyl) isocyanuric acid, and the second antioxidant is 2, 4, 6-tri (3 ', 5'-di-tert-butyl-4 '-hydroxybenzyl) mesitylene. Wherein the second antioxidant is bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate and / or pentaerythritol tetra (3-lauryl thiopropionate), and the second antioxidant is a mixture of the first antioxidant and the second antioxidant. As a semiconductive shielding material, the composition provided by the invention not only has excellent insulation yellowing resistance, but also has excellent mechanical property and conductivity, and ensures better application of the material in preparation of power cables.

The invention provides a low-GI biscuit raw material composition which comprises the following components in parts by weight: 0.1-0.6 part of nanocrystallized bamboo fiber cell walls, the nanocrystallized bamboo fiber cell walls are extracted from bamboo green, are edible and have one-dimensional characteristics, the transverse size is below 100nm, the longitudinal size is above 1mu m, cellulose in the nanocrystallized bamboo fiber cell walls has the crystallinity of 80%-95%, and the grain size of the cellulose in the nanocrystallized bamboo fiber cell walls is 100 nm. The dispersion liquid of the nanocrystallized bamboo fiber cell walls in water has the viscosity of 200 Pas or above when the mass concentration of the dispersion liquid is 0.5%, 40-70 parts of low-gluten flour, 20-35 parts of whole wheat flour, 8-20 parts of grease selected from natural butter, coconut oil or non-hydrogenated vegetable butter and 10-25 parts of sugar substitutes, and the sugar substitutes comprise at least one of erythritol and maltitol; the total mass content of the dietary fibers is greater than or equal to 15%. The beverage has a high low-GI effect, a suitable taste and good crush resistance. Methods of making low GI biscuits and low GI biscuits are also provided.

The application provides a thermal infrared hyperspectral characteristic wave band selection method based on an improved particle swarm algorithm, and comprises the following steps: step 1, preparing a mixed salt ore sample, collecting a hyperspectral emissivity spectrum of the mixed salt ore sample, measuring the mass content percentage of each mixed salt mineral in the mixed salt ore sample as a data set for selecting a characteristic wave band and predicting a content; step 2, taking the data set in step 1 as input, and establishing a prediction model of a characteristic wave band combination of each substance in the mixed salt ore and corresponding content prediction based on the improved particle swarm algorithm; step 3, based on the prediction model in step 2, predicting the characteristic wave band combination of each substance in the unknown mixed salt ore and the corresponding content, collecting the content percentage of the mixed salt ore and verifying the result. The improved particle swarm algorithm does not need to artificially adjust the parameters of the algorithm, and the obtained wave band combination prediction result is stable.

The invention discloses a catalyst for preparing 1, 3-propylene glycol through glycerol hydrogenation and a preparation method and application of the catalyst. The catalyst comprises a carrier, an active component loaded on the carrier and an auxiliary, the active component is Pt, a phosphide of Pt and a phosphide of W, and the auxiliary agent is La or Ba; according to the weight ratio of 100%, the loading capacities of the Pt, the W, the phosphorus and the auxiliary agent are respectively as follows according to the mass content of the carrier: 1-4% of Pt, 3-15% of W, 0.1-5% of phosphorus and 0.1-0.8% of the auxiliary agent. The catalyst is high in stability, is suitable for hydrogenation production of 1, 3-propylene glycol from a glycerin aqueous solution, is high in product selectivity and yield, can reduce the components of the catalytic reaction, is mild in reaction conditions, meets the requirements of green chemical industry, and has great economic values and industrial application prospects.

The invention discloses a design method for improving corrosion resistance of a copper-nickel alloy by adding alloy elements. The design method comprises the following steps: screening the alloy elements; the first screening condition is that the solid solubility of the to-be-added alloy element in the copper-nickel alloy is larger than 0.1 wt.%, the second screening condition is that the standard electrode potential of the to-be-added alloy element is smaller than that of Ni, the third screening condition is that the deposition line of the to-be-added alloy element is lower than that of Cu2O, and the fourth screening condition is that the to-be-added alloy element is non-noble metal; based on the screening result, the mass percentage content range of the alloy elements is determined according to the maximum solid solubility of the alloy elements in the copper-nickel alloy; the ratio of the nucleation rate to the growth rate is larger than 104, and the corrosion rate is stabilized to be not higher than 0.02 [mu] m / a along with time, and the mass content of the alloy elements is obtained through optimization; and the final components and content of the added alloy element copper-nickel alloy are determined on the basis of the optimization result, and the corrosion resistance of the alloy element copper-nickel alloy is verified through experiments. The invention provides a design thought for the corrosion-resistant alloy with slowly dissolved main elements.

The application discloses a HIPS alloy material and a preparation method and application thereof, and belongs to the technical field of high polymer engineering plastics. The HIPS alloy material comprises the following components in parts by mass: 58-82 parts of HIPS resin, 18-42 parts of ASA glue powder, 10-18 parts of phosphorus flame retardant, 3-9 parts of nitrogen flame retardant, 4-12 parts of hollow glass microbead and 1-9 parts of compatibility agent. The mass content of acrylate in the ASA glue powder is 53-66%. The average particle size of the hollow glass microbead is 38-82 mu m. The HIPS alloy material provided by the application has excellent flame retardance and mechanical properties. The preparation method is simple and is beneficial to actual production.

The invention relates to the technical field of mineral resources, in particular to a comprehensive assessment method for miscellaneous ores, which comprises the following steps: establishing a sinter cup test database, dynamically updating mineral powder variety and performance data, taking uniform samples of miscellaneous ores to be assessed with the weight not less than 500g, dividing into 3 parts, respectively detecting miscellaneous ore iron grade, harmful element mass content and impurity mass content for the 3 parts of samples, the iron grade score, the harmful element score and the impurity score of the corresponding sample are calculated, comprehensive evaluation calculation is carried out according to the formula that the comprehensive score = (A * T1) + (B * T2) + (C * T3), A is the iron grade score of the first sample, and T1 is the weight of the iron grade score; b is the score of the harmful element of the second sample, and T2 is the weight of the score of the harmful element; c is the impurity score of the third sample, and T3 is the weight of the impurity score; one-sided evaluation is avoided, the use demonstration period of some mineral powder is effectively shortened, the situation that the best purchase opportunity is missed due to uncertain factors such as the market and indexes is avoided, and the purchase cost is reduced.

The invention belongs to the technical field of preparation of cordierite materials, and particularly relates to a cordierite ceramic material as well as a preparation method and application thereof. The preparation method of the cordierite ceramic material comprises the following steps: 1) mixing ferrochrome waste residue and fly ash according to a mass ratio of (3-5): (5-7), heating to obtain a molten mixture, and then carrying out water quenching treatment to obtain a frit raw material; and 2) mixing the obtained frit raw material with SnO2 according to a mass ratio of (95-99): (1-5), grinding, and calcining to obtain the cordierite ceramic material, the calcination treatment comprises preheating, first calcination and second calcination, and the heating rate from preheating to first calcination is 8-12 DEG C / min. The whole process is matched, and the obtained cordierite ceramic material is high in cordierite phase mass content, low in thermal expansion coefficient, high in bending strength, excellent in thermal stability and good in high-temperature performance and mechanical performance.

The invention belongs to the technical field of polypropylene preparation, and particularly relates to a propylene polymer, a preparation method thereof and a polypropylene composition. The propylene polymer is characterized in that the propylene polymer comprises a propylene homopolymer as a matrix, and the content of the propylene homopolymer is greater than or equal to 99 wt%; the composition comprises a polymer nucleating agent, and the mass content of the polymer nucleating agent is 1-1000 ppm; the matrix comprises 0.1 wt%-10.0 wt% of ultra-high molecular weight components with the molecular weight M greater than or equal to 10,000,000; m < z + 1 > of the propylene polymer is greater than or equal to 6000 * 10 < 3 >, and M < z + 1 > / Mn is greater than or equal to 100. The propylene polymer provided by the invention has both processability and mechanical properties, and the rigidity and toughness of the mechanical properties are remarkably improved at the same time.

Dry mortar composition, in particular adhesive mortar. The invention relates to a dry mortar composition, preferably adhesive mortar, having an uncompacted density between 900 g / L and 1400 g / L and comprising at least one air-entraining agent at a mass content between 0.1% and 2%. The invention also relates to a wet mortar obtained from mixing this dry mortar composition, as well as a method for fixing tiles to a substrate using this dry mortar composition.

The application discloses a high-strength dual-phase steel with excellent low-temperature toughness and corrosion resistance and a production method thereof, and belongs to the technical field of steel rolling production. The chemical composition and mass content of the dual-phase steel are as follows: C: 0.06-0.12%, Si: 0.15-0.4%, Mn: 1.8-2.5%, Cr: 0.3-0.6%, Nb: 0.015-0.03%, Mo: 0.20-0.25%, Cu: 0.2-0.4%, Ni: 0.3-0.8%, Ti: 0.008-0.018%, N: 0.0030% or less, P: 0.025% or less, S: 0.002% or less, and the balance of Fe and inevitable impurity elements. The production method comprises a slab heating, rolling and continuous annealing process. The obtained dual-phase steel has uniform ferrite and martensite structures, good strength and toughness matching, and excellent low-temperature toughness and corrosion resistance.

The invention relates to the field of aluminum oxide preparation, and discloses modified aluminum oxide as well as a preparation method and application thereof. The modified aluminum oxide comprises aluminum oxide, a first modified component and a second modified component; the first modified component is selected from at least one of IVB group metal elements; the second modified component is a sulfur element; the mass content of the first modification component is 0.01-5% and the mass content of the second modification component is 0.1-5% by element on the basis of the alumina dry basis weight of the modified alumina. The catalyst prepared by using the modified alumina as the carrier is used in the field of catalytic reforming, especially in the field of naphtha catalytic reforming, and has high reaction activity and aromatic hydrocarbon selectivity.

The invention discloses a wastewater treatment method and system, and the treatment method comprises the following steps: carrying out first concentration crystallization treatment on wastewater to obtain a concentrated treatment solution, carrying out solid-liquid separation treatment on the concentrated treatment solution to obtain ammonium sulfate and a first mother solution, and monitoring the specific gravity of the first mother solution and the mass content of phosphorus in the first mother solution, the wastewater comprises NH4 < + >, SO4 < 2-> and PO4 < 3->; when the specific gravity of the first mother liquor and the mass content of the phosphorus element meet first preset values, carrying out second concentration and crystallization treatment on the first mother liquor to obtain ammonium dihydrogen phosphate and second mother liquor; when the specific gravity of the first mother liquor and the mass content of the phosphorus element do not meet the first preset value, mixing the first mother liquor with the wastewater, and then carrying out first concentration crystallization treatment. According to the treatment method, the impurity content in ammonium sulfate can be reduced, the added value of byproducts is improved, and the economic benefit of wastewater treatment is improved.

The present invention provides a method for the comprehensive utilization of coal gangue by grading and separating different components, which relates to the technical field of resource utilization of solid waste. Based on the differences in the component composition and technological properties of coal gangue, especially based on the different mass content ratios of SiO2 / Al2O3 in coal gangue, different crushing and screening processes are adopted respectively. Through multi-stage crushing, precise grading and separation technologies, the coal, gangue (soil) and stone in coal gangue are separated and sorted to obtain crushed stones, manufactured sand, soil and coal with different particle sizes. Then, according to their respective compositional and technological property differences, fuel utilization, recycled soil utilization, fertilizer preparation utilization and CO2 absorption and fixation material preparation utilization are carried out respectively, so as to realize the comprehensive utilization of coal gangue by grading and separating different components.

The invention relates to a special SEBS (styrene-ethylene-butylene-styrene) material for toughening polypropylene, a preparation monomer of the special SEBS material comprises styrene and butadiene, the molecular weight of the special SEBS material is 8.9-11.3 * 10 < 4 >, and in the special SEBS material, the mass content of a styrene chain segment is 13-50%, and the mass content of a 1, 2 structure chain segment of butadiene is 20-65%. According to the present invention, the SEBS structure is specifically designed, such that the room temperature impact strength and the low temperature impact strength of the PP are effectively improved, and the low room temperature shrinkage rate is provided; when the material is used for toughening polypropylene, excellent balance of high rigidity and high toughness of PP can be realized only by using a small amount of SEBS special material; the toughness of homo-polypropylene resin and co-polypropylene resin can be effectively improved, high rigidity can be kept, and meanwhile the preparation method of the polypropylene composite material is simple, efficient, simple in technological process and relatively low in cost.

A turbomachine part includes a nickel-based superalloy substrate including, in mass content, 5.0% to 8.0% cobalt, 6.5% to 10% chromium, 0.5% to 2.5% molybdenum, 5.0% to 9.0% tungsten, 6.0% to 9.0% tantalum, 4.5% to 5.8% aluminum, hafnium in a mass content between 500 ppm and 1100 ppm, and optionally including niobium in a mass content less than or equal to 1.5%, and optionally at least one of carbon, zirconium and boron each in a mass content less than or equal to 100 ppm, the remainder being composed of nickel and unavoidable impurities.