30 results about "Invar" patented technology

An enchance recording head design provides conduction and mechanical restraint control in order to minimize the pole tip protrusion and the head temperature resulting from the thermal heating of the magnetic recording head during operation. In one embodiment, the recording head includes a hybrid diffuser formed within an insulation layer, at a predetermined distance from the head write section. The hybrid diffuser is comprised of a thermal conduction layer with high thermal conductivity, such as gold or copper, and a mechanical restraint layer having near zero CTE, such as a 60-80% face-centered-cubic NiFe (Invar) material. The hybrid diffuser is recessed from the ABS to prevent the delamination of the hybrid diffuser due to the otherwise displacement incompatibility between the inner insulating layer and the hybrid diffuser at the ABS.

An enhanced recording head design provides thermal diffusion and thermal expansion control in order to minimize the pole tip protrusion resulting from the thermal heating of the magnetic recording head during operation. In one embodiment, the recording head a thermal restraint section formed above a write section, and is made of a 60–80% face-centered-cubic NiFe (Invar) material. According to another embodiment, the thermal restraint section is formed under the read section. According to yet another embodiment, one thermal restraint section is formed above the write section, and another thermal restraint section formed under the read section.

A low cost micro-electronic package for MEMS applications includes a package substrate, a MEMS device and a buffer insert which is placed between the MEMS device and the package substrate. The buffer insert has a coefficient of thermal expansion (CTE) which is compatible with the material of the MEMS device and is sufficiently rigid to isolate the MEMS device from thermal, mechanical and other physical stresses applied to the package substrate. In an embodiment, the package is formed as an integrated device which includes both the MEMS device and a signal conditioning integrated circuit, potentially found in the same die. The substrate insert may be made of a material having a CTE value compatible with silicon (Si), such as Kovar, Invar, or an appropriate ceramic material or the like.

The invention relates to a preparation method of an invar-based composite material, in particular to a preparation method of a high-strength ultralow-expansion invar-based composite material. The invention aims to solve the technical problems that the deformation machining technique for the high-strength invar is complex and the high-strength invar is difficult to be machined into large-size components. The method comprises the following steps: 1. preparing high-purity titanium powder and carbon powder precast blocks; 2. smelting invar to obtain molten mass; 3. adding the precast blocks into the molten mass in step 2, and casting to obtain cast ingots or castings while keeping the temperature constant; and 4. carrying out heat treatment to obtain the high-strength ultralow-expansion invar-based composite material. Compared with the prior art, the high-strength ultralow-expansion invar-based composite material in the invention has the advantage of simple control on composition and technique and low cost, can be directly formed by casting without complex deformation hardening technique, does not contain precious metals, and particularly can control the coefficient of expansion of the invar at low level while greatly enhancing the strength of the low-expansion invar.

The invention relates to metallographic chemical corrosive agents and preparation methods thereof, in particular to a metallographic corrosive agent for an invar welded joint welded by using M93 welding wires and a preparation method for the metallographic corrosive agent. The metallographic corrosive agent and the preparation method thereof aim at solving the metallographic problem of the invar welded joint welded by using the M93 welding wires. The metallographic corrosive agent is prepared by mixing HCl solution with the mass concentration of 36-38%, FeCl3 and water. The preparation method includes: A, accurately weighing HCl solution, FeCl3 and water; B, adding the weighed FeCl3 into the water, and stirring until completely dissolving to form a uniform mixture; and C, slowly adding the HCl into the mixture to form the metallographic corrosive agent, namely, preparation of the metallographic corrosive agent for the invar welded joint welded by using the M93 welding wires is finished.

The invention discloses a concrete temperature stress testing machine with a temperature deformation self-compensation function and belongs to the technical field of concrete temperature stress and deformation testing simulation. A polished rod is manufactured from No.4J36 invar, a left fixed end, a right fixed end, fixed end universal joints and movable end universal joints are manufactured from No.4J36 invar, and a fixed chuck, a movable chuck and a load sensor are manufactured from No.45 steel. Parts of the testing machine are made from different steel materials, the combination length of the parts is designed according to a certain proportion, when outside temperature changes, the total temperature deformation difference generated by all steel parts of the concrete temperature stress testing machine can be zero, accordingly temperature deformation, caused by outside temperature change, of steel of the testing machine is offset, and temperature deformation self-compensation of the testing machine is achieved.

The invention relates to a preparation method of a Cu/Ag (Invar) composite material for electronic packaging. A chemical plating solution system of which a main salt is AgNO3 and a reducing agent is KNaC4H4O6 is used for chemically plating Ag on Invar powder of which the average particle size is 25 to 50 mum so as to prepare chemical plating Ag (Invar) composite powder, the Ag (Invar) composite powder and Cu powder of which the average particle size is 25 to 50 mum are used as raw materials and are mixed according to the component Cu of 30 to 50wt%, then zinc stearate of which the overall weight is 0.5wt% of the raw material powder is added as a lubricating agent, the raw materials are mixed by a double-shaft roller, are pressed in one direction under 300 to 600 MPa, are protected in a high-purity H2 atmosphere, are insulated for 1 to 3 h at 650 to 800 DEG C and are sintered under normal pressure so as to prepare the Cu/Ag (Invar) composite material, and a multi-pass cold rolling and annealing thermomechanical treatment process is adopted to realize the near-complete densification of the composite material. The prepared 40wt% Cu/Ag (Invar) composite material has excellent overall performance and can be used as a high-performance electronic packaging heat sink material, the density can reach 99%, the hardness is HV256, the coefficient of thermal expansion is 11.2*10<-6>K<-1>, and the heat conductivity is 53.7 W.(m.K)<-1>.

The invention provides a method for rapidly detecting Salmonella in foods and relates to the technical field of food detection. A PCR method is used to detect inVA genes of Salmonella in a to-be-tested food sample. The method includes the steps of adding the to-be-tested food sample into buffered peptone water to enrich the bacteria, then washing the bacteria with physiological saline, boiling lysed cells, and centrifuging to obtain the supernatant; taking the obtained supernatant as a PCR reaction template, and using detection primers of Salmonella inVA gene for PCR detection; wherein the detection primers are as follows: an upstream primer inVAF:5'-tcctccgctctgtctactta-3', and a downstream primer inVAR: 5'-accgaaatattcattgacgtt-3'. The detection results of the method are consistent withthose of a conventional culture method and a BAX system, the detection limit is 100cfu/25g, and the accuracy is 100%.

The invention relates to the technical field of ultrasonic transduction, in particular to a transduction unit for an ultrasonic transducer. The transduction unit comprises a sealed invar shell and a piezoelectric ceramic ring arranged in the invar shell. A silver layer on the outer side of the piezoelectric ceramic ring is tightly attached to the invar shell, an oil medium is removed from the position between the piezoelectric ceramic ring and the shell, and the transduction efficiency is improved. Meanwhile, the silver layer on the outer side of the piezoelectric ceramic ring is tightly attached to the invar shell, so that heat generated by the piezoelectric ceramic ring is dissipated out through the invar shell. Under the condition that heat dissipation is not affected, the problem that ultrasonic wave losses of a transduction unit of an existing ultrasonic transducer exist is solved, in addition, a sealed shell structure is adopted in the transduction unit, so that transmission media are prevented from entering the transducer in the use process, in addition, the heat expansion coefficient of invar is smaller than the heat exchange coefficient of piezoelectric ceramic, so that the fitness between the piezoelectric ceramic ring and the invar shell is better along with increasing of the temperature, and the working performance of the transduction unit is more stable.

A grilling component (10) employed to grill food items includes a grilling surface (16) made of a material having a low constant of thermal expansion. In one example, the grilling surface (16) is made of Invar. Invar is a metal allow comprised of Iron and 36% Nickel, and may include other trace elements. Invar has a low constant of thermal expansion and therefore moves and expands very little when heated. The grilling surface (16) further includes a non-stick coating (18), such as Teflon. The grilling surface can also be a conveyor belt (32) which travels over a heater (26).

The invention belongs to the field of material melting welding and particularly relates to an invar and aluminum alloy dissimilar metal electron beam welding method. Electron beams are adopted as theheat source, an intermediate layer is added between invar and aluminum alloy, electron beam welding between the intermediate layer and the invar is performed first in a two-step butt welding mode, andthen electron beam welding between the intermediate layer and the aluminum alloy is performed; and the material of the intermediate layer is a material which does not react with the invar to generateintermetallic compounds, and the linear expansion coefficient of the material falls in between those of the invar and the aluminum alloy. According to the invar and aluminum alloy dissimilar metal electron beam welding method, the intermediate layer made of steel or copper or a metal which does not react with the invar to generate brittle intermetallic compounds is added, the complexity of metallurgical reaction between the invar and an aluminum joint can be reduced, ternary metallurgical reaction or polybasic metallurgical reaction is converted into binary metallurgical reaction, and the metallurgical regulation difficulty is reduced.

The invention discloses Cu/INVAR/Ni composite brazing filler metal for heterogeneous connection of hard alloy and steel and a laser welding and brazing process thereof, and belongs to the technical field of laser brazing. The Cu/INVAR/Ni composite brazing filler metal is of a sandwich sheet structure composed of a Cu foil, an INVAR sheet and an Ni foil, the Cu foil is arranged on one side of steel in advance, the Ni foil is arranged on one side of hard alloy in advance, the INVAR sheet is located between the Cu foil and the Ni foil, the thickness of the Cu foil is consistent with that of the Ni foil, the thickness of the INVAR sheet is larger than that of the Cu foil and that of the Ni foil, and laser welding and brazing is conducted through an automatic platform based on a laser, a robot and an outer shaft positioner. According to the Cu/INVAR/Ni composite brazing filler metal and the laser welding and brazing process thereof, the stress between the hard alloy and the steel with overlarge difference of physical properties such as thermal expansion coefficients is buffered, the welding heat input is reduced, and the problem of cracks caused by overlarge heat input in laser welding of the hard alloy and the steel is solved.

The invention relates to an insulating material suitable for liquid hydrogen energy storage as an inner container of a liquid hydrogen storage bottle (tank). The insulating material is characterized in that the insulating material suitable for liquid hydrogen energy storage, especially a ceramic material, is used to make the inner container of the liquid hydrogen storage bottle (tank); an inner container body of the insulating ceramic bottle (tank) is seamlessly wrapped with a heat preservation body made of double-layer vacuum invar, and an opening of the inner container body of the insulatingceramic bottle (tank) and an opening of the double-layer vacuum invar heat preservation bottle (tank) are jointly designed to be an insulating valve (3) resistant to high pressure.

The invention relates to a telescopic invar barcode leveling rod, and a precise leveling method using cooperation of the telescopic invar barcode leveling rod with an even number of stations. The telescopic invar barcode leveling rod comprises an inner rectangular steel tube, an outer rectangular steel tube and spiral pins, the inner rectangular steel tube is sleeved in the outer rectangular steel tube, the outer rectangular steel tube is provided with the spiral pins, the front side surface of the outer rectangular steel tube is provided with an invar barcode ribbon, and the rear side surface of the outer rectangular steel tube is provided with a leveler. Even-number station measurement between a point A and a point B is carried out through the measurement method when the telescopic invar barcode leveling rod is used to measure a height difference between the point A and the point B, so the measurement precision in the leveling process is guaranteed. The telescopic invar barcode leveling rod has the advantages of simple structure, convenient use and carrying, economy cost saving, and reaching of precision requirements in the leveling process by means of the precise leveling method.

The invention discloses a forging process special for mask plate support alloy Invar 36. The forging process comprises the steps that after the surface of Invar36 alloy is cleaned with acetone, the cleaned Invar36 alloy is placed into a resistance furnace to be heated, the temperature in the resistance furnace is 950-980 DEG C, and heat preservation is conducted for 10-18 min; two-upsetting and two-drawing cogging forging is conducted, the first upsetting deformation is 30-35%, then first drawing is conducted, the drawing deformation is controlled to be 14-35%, and the Invar36 alloy is fed into a heating furnace at a temperature of 1100 DEG C for solution treatment; the second upsetting deformation is 50-60%, then second drawing is conducted, the drawing deformation is controlled to be 10-40%, and the Invar36 alloy is fed into the heating furnace at a temperature of 1050 DEG C for solution treatment, wherein the first solution treatment is conducted for 1.5 hours at the temperature of1100 DEG C, and the second solution treatment is conducted for 1 hour at the temperature of 1050 DEG C; and through two-upsetting and two-drawing cogging forging, the alloy is repeatedly forged, carbide in the alloy is better smashed, internal grains are finer through high-temperature calcination and repeated forging, and the strength, hardness, abrasion resistance, fatigue strength, toughness andthe like of channel steel are improved through quenching.