| It is used co-precipitation method to prepare pre-alloy powder in this article.With the copper raw material of chloride ? ferrous chloride ? tin chloride ? nickel chloride and precipitating agent of oxalic acid,the copper pre-alloy powder was prepared.The effects of different processes of the reaction solution on the particle size and the powder yield of the pre-alloyed powder were emphatically investigated;The effects of the calcinations' temperature,the reduction temperature and the reduction time on the particle size and the powder yield of the pre-alloyed powder were also studied;at the same time,the effect of prealloyed powders prepared by different preparation methods on the mechanical properties of the samples was systematically discussed by means of universal material testing machine?digital density meter and Rockwell hardness tester.The application of pre-alloy powders with different copper content in saw blade was researched.The results showed that: when the dosage is 5,the aging time is 40 min,the reaction temperature is 50 ? and the solution concentration is 1.0mol/L,the particle size of the precursor powder is the smallest and the powder yield is the highest.The surface of the precursor is smooth and the shape is mostly rod-shaped,irregular shape,mostly polyhedral,the average particle size is 2~5?m;and the precursor powder has crystal structure,but the diffraction peak is relatively wide.The grain size of the precursor powder is about 2?m at 500 ?,and the powder is still consistent with the precursor powder.The phase remains basically unchanged and the diffraction peak becomes sharp.The effects of different reduction temperature and different reduction time on the particle size and oxygen content of the powders were studied.After the reduction of hydrogen gas,the powder particles obtained from the scale can be seen between about 2~3? m,and the particles are intertwined;The proportion of the elements of the pre-alloy powder is almost the same from that of the raw material added at the time of feeding.When the sintering temperature is 820 ?,the holding time is 5min and the sintering pressure is 4MPa,the performance was greatly improved,and this process parameter can be used as the best combination of sintering parameters.The properties of the preparation of three kinds of powders were studied by the combination of powder,atomization and coprecipitation.The results showed that: Co-precipitation method of powder preparation of sample bending strength is up to 1155.2MPa,which is higher 11.6% than the sample of atomization(1021.2MPa),and which is higher 23.6% than the sample of elemental mixed powder(882.5MPa);Co-precipitation method of powder preparation of sample hardness up to 112.5,which is higher 5.03% than the sample of atomization(106.9),and which is higher 19.24% than the sample of elemental mixed powder(90.85);Co-precipitation method of powder sample preparation of the highest density of 7.83 g/cm3,which is higher 2.04% than the sample of atomization(7.67 g/cm3),and which is higher 3% than the sample of elemental mixed powder(7.63g/cm3).By comparison of cutting performance of saw manufactured by pre-alloy powders of different copper contents,the saw blade cut the same length of granite,the results showed that: when the copper content is 50%,the weight loss of the saw blade was the smallest of 1.16 g,the wear ratio was also the lowest of 9.67 g/m~2,the saw blade has the best performance,and the sharpness of the saw blade is the highest. |
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