The preference of raw materials. Graphite graphite is a crystalline material of a layered structure. In a graphite crystal, a carbon atom forms a hexagonal layered structure in a closed six-carbon polycyclic state, and a distance between adjacent carbon atoms in its same planar layer is 01142 nm to combine Strong covalent bonds are connected. The distance between the layer and the layer of carbon atoms is 01335 nm, which is connected by the weaker van der Waals force. When the tangential force is applied to the crystal layer, the layer is easy to slide between the layers. The friction coefficient of graphite is about 0108 at 300e, the decomposition temperature is 450e, the decomposition products are CO, CO 2 , and the molybdenum disulfide molybdenum disulfide also has a layered crystal structure, so the friction coefficient is small, but since the temperature is greater than 250e, That is, decomposition occurs, and the friction reducing performance gradually fails, and the decomposition product SO 2 is a corrosive gas, which is harmful to the metal material. It is clear that molybdenum disulfide is not an ideal choice at high temperatures. Nickel powder metal nickel has good chemical stability, high hardness, good high temperature strength and good plasticity. The combination of graphite and nickel powder has a lower coefficient of friction and a higher compressive strength, so that it has better adhesion resistance and bite resistance.
In order to make the nickel powder and colloidal graphite have good matching, the particle size of the nickel powder should reach the micron level. Therefore, the nickel powder prepared by nickel carbonyl chemical vapor deposition is selected: Ni+4CO 50e Ni(CO)4 Ni(CO)4 150360e Ni+4CO Since the impurities in the metallic nickel do not enter the gas phase at normal temperature, the nickel carbonyl method The produced nickel powder has fine particle size, high purity, nickel content of more than 9919%, and particle size of micron. Silicone is a colorless, transparent liquid that is non-corrosive, has good thermal stability, and has excellent radiation resistance. In addition, the silicone resin has an RS-iO-reactive group, and is further activated after adding a trace amount of a catalyst, and adsorbs a trace of water molecules on the surface of the workpiece to promote the hydrolysis and condensation reaction of the silicone resin, so that the original low molecule gradually condenses and becomes sticky. A continuous dense film is formed on the surface of the workpiece to separate the metal surface from external water molecules and corrosive media, thereby improving corrosion resistance. Paraffin oil is derived from petroleum liquid saturated hydrocarbon mixture, colorless oily liquid, density 860910kg/m 3 , freezing point -20e, flash point (open cup) 210e, non-toxic, can be mixed with most fatty oils, heat stable Good sex. Polytetrafluoroethylene PTFE is a good material for reducing friction and sand screening machinery. It has excellent chemical stability, but its coefficient of linear expansion is very large, which is (825)@10 -5 e -1, which is 1020 different from ordinary metals. Times. The thermal conductivity is 14165W/(mK), which is about 100 times different from the metal. According to the analysis of the performance of the above-mentioned inorganic and organic raw materials, combined with the high temperature resistance requirements, the fluororesin and sulfide lubricating materials are excluded. The graphite and metal nickel powder are mainly used as inorganic lubricating materials, and silicone resin is used as an organic lubricating material. This is the focus of research, repeated trial and comparison, and with viscosity control agents, anti-rust additives. After heating, stirring, dispersing and grinding, it is processed into a homogenous paste-like bolt anti-seize high-temperature anti-friction material (abbreviated as anti-biting material).
Main performance test. Heating test piece specifications: 100mm@50mm@1mm 铌 high temperature resistant alloy. Sample preparation: The test piece was sufficiently degreased and dried, and the anti-bite material was brushed on one side of the test piece to a thickness of 5080 Lm. Test method: temperature test 250e, 3 days, 300e, 7 days for one cycle. Visual inspection: Zoom in 10 times to observe. Test results: After the test piece was heated for 4 cycles and 40 days in total, the appearance of the coating did not change significantly at the beginning, and remained oily and shiny; slight knocking did not fall off. The Falex test was carried out according to the relevant standard method of Falex, ZBE34020-89, ZBE34005-87, ZBE34004-87, and the test was commissioned by the Institute of Petrochemical Science. The results are as follows: according to ZBE34020-89, the friction factor of the anti-bite material, the test result is 010801105 under the load of 1335N. According to ZBE34005-87 lubricant wear performance test (Falex axis and V-block method), anti-biting material wear life Under 3115 N load, continuous friction to failure time was 342,708 s. According to the ZBE34004-87Falex test B method, that is, the method for measuring the extreme pressure performance of the lubricant, the ultimate pressure failure load of the anti-bite material is 6450 7784N. A blank sample without anti-biting material has an extreme pressure failure load of 1110N. Bolt anti-seize test specimen: bolt material 1Cr18Ni9T, i specification M16@2; nut processed into a half-hole structure. 3 sets of bolts and blank specimens coated with anti-bite material. Test method: The M16@2 nut is clamped on the vise, and the asbestos washer is placed at the bottom of the nut. The bolt head is pressed down to the bottom. The torque at the time of seizure is measured by a torque wrench. The applied torque is 20Nm, 40Nm, 60Nm, 80Nm, 100Nm, 150Nm, 200Nm, 250Nm, 300Nm, and the torque is applied for 10s per stage, and then unloaded. If it cannot be unloaded, it means bite. Blank: 6080Nm is all killed, and the thread is broken after sawing. Anti-biting material: 300Nm (maximum scale of torque wrench is 300Nm), can be smoothly unloaded, and the thread is intact.
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