| Objective: This experiment is a new type of nickel-chromium alloy surface treatment—nickel-chromium alloy surface spraying of molybdenum powder, tests the coating adhesion strength, wear resistance and porcelain bond strength, observed the coating can meet the clinical requirements and provided the experimental basis for clinical application.Methods: According to GB 8641-1988 standard, produced tensile strength tests casting with 18, the castings were randomly divided into A, B groups. Including group A, after surface purification, spraying molybdenum powder which accordance the surface of the plasma spraying parameters, B group was not treated. Between the A, B groups were pared into one group, each set of castings were bonded together with E-7 glue, and installed in the MTS-810 tensile testing system which measured tensile bond strength test. Record the maximum load when the coating fracture, and calculated the tensile bonding strength according to the formulaσb=4F/πd2According to GB 8641-1988 standard, produced wear tests casting with 20, the castings were randomly divided into A, B groups. Including group A, reference to the requirements of plasma spraying, cleaned casting surface, and sprayed molybdenum powder on the casting surface accordance with the parameters of plasma spraying, B group was not spraying. The A, B groups of casting were placed in MLD-10 type of abrasive wear test machine, weared the castings uninterrupted. Calculate the weight loss after 1 hour, Choose one casting of the A group for scanning electron microscopy, to test the coating wear resistance.According to ISO 9693 standard, produced three-point bending test casti- ngs with 21, choose one of the castings randomly for scanning electron micro- scope after spray, others were divided into A, B groups randomly, which requ- ired A group for surface cleaning and plasma spraying of molybdenum pow- der, and B group was not handled. Then A, B groups were fixed in universal dynamometer on three-point bending test, record the maximum load when the porcelain off, according to the formula P = F / S to calculation bond strength calculation.All tests were setted laboratory ambient temperature (23±2)℃, relative humidity of 44% -56%, simulated oral environment as possible.Results: The results of tensile adhesive strength test was (44.678±3.71), which greater than the ISO standard requirements of 25 MPa, and by statistical analysis P<0.05, statistically significant, the interface of scanning electron microscopy revealed no obvious defects. Wear test results for the test group (0.101±0.028), the control group (0.212±0.045), by statistical analysis P<0.05, statistically significant. Three-point bending test results for experimental group (20.67±2.389), the control group (45.36±0.883), by statistical analysis P<0.05, statistically significant, but the results of the experimental group was less than the ISO standard requirements of 25 MPa.Conclusion: 1 Nickel-chromium alloy after plasma spraying of molybde- num powder, the coating bond strength is greater than ISO standards, and meet the clinical requirements of oral, with a high clinical application possible.2 Nickel-chromium alloy after plasma spraying of molybdenum powder, the coating wear resistance than the untreated alloy, can meet the clinical requirements.3 The coating has high bond strength combination and wear resistance, which provide experiments basis for clinical applications such as metal full crown , inlay and post.4 Nickel-chromium alloy after plasma spraying of molybdenum powder, and routine operations porcelain, the porcelain bonding strength is less than ISO standards, can not meet the clinical requirements. |
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