Performance Study On Plating Nickel Of Engine Cylinder

With the demand of light weight engine is more stronger,in the past few years, the large capacity engine is improving and working on the light weight cylinder block. The aluminum nickel plating cylinder has the same coefficient of thermal expansion with piston, has these strong points for better thermal conductivity and light weight, application are more popular. The improving for adhesion of Ni-SiC plating is the key point to ensure the aluminum cylinder block performance meeting requirement.1. This study makes the improving of SiC plating adhesion as the target, chooses the samples with typical problems, analyzes with characterization of microstructure method, surmise the microstructure of root cause for this failure.2. As an example with 650 mL engine, present the process correcting proposal to improve the adhesion. Making the samples and comparing the metallographic structure for the improved parts and before. After improving, confirmation the microstructure feature caused the adhesion failure eliminated.3. Assemble the improved parts to engine for 300 h enduring test. Comparing with dimension of the cylinder and relative parts after testing and before, also comparing with the performance of engine, the wear extent of parts and degradation rate of engine performance both are in the tolerance, so reach the goal and the improvement is effective.By the analysis and implement of improvement, prove it is right that microstructure caused by Ni-SiC adhesion failure has been found out. The process action to increase the adhesion is effective to improve the microstructure, finally the cylinder bore macrostructure and engine performance to be improved obviously.This study sums up the failure mode and issues during plating process, including the root cause investigation and judgment with microstructure and macrostructure, all these should be the experience for further study on the plating and for widely implement on practical engines,it is valuable as a reference.