【作者】

Minoru Kawanishi

【摘要】

该论文已在赫尔辛基举行的第28届CIMAC世界大会上发表，论文的版权归CIMAC所有。 More than ten years ago, the current thermal spray coating, which has a superior wear resistance and a good scuffing performance, had started applying to piston rings for low speed diesel engine. However, the current market trend of low speed diesel engine requires a higher durability in corrosive condition due to the slow steaming. Under such a circumstance, Riken have successfully developed a new thermal spray coating with a higher durability under the corrosive condition comparing to the current coating. Riken will show the latest technology, how the durability of the new spray coating has been improved. The key word is “Complicated microstructure”. We could confirm the mechanism of how the wear occurs on the coating by performing rig tests. In this case, we could find out the indicative vestiges that particles dropped out from the surface of coating. These dropped-out particles made the unacceptable abrasive wear on the sliding faces of both piston ring and liner material. Thus, it was considered that a better anti-wear performance is needed in order to reduce the dropped-out particles. We concluded that the new thermal spray coating should have complicated microstructure, because complicated particle interface prevents the particles from dropping out. The complicated microstructure would be achieved by optimizing the particle size and ratio of chromium carbide, and getting higher energy for well melting powder. In general, harder coatings show better anti-wear performance. It is also well known that the larger particles and the higher ratio of chromium carbide make spray coatings harder. On the other hand, such coatings easily make particles drop out, and it can’t get good anti-wear performance. Finally, we found out the best combination of the particle size and the ratio of chromium carbide. We confirmed that the combination of smaller particle size compared to the current specification, and middle ratio of chromium carbide has the best anti-wear performance without any dropped particles. As the results, we achieved to reduce not only the wear of spray coating by approximately 35%, but also the wear of liner material by approximately 30%. Moreover, we could get excellent anti-wear results in the field under low feed rate condition.

【会议名称】

第28届CIMAC会议

【会议地点】

芬兰 赫尔辛基

【下载次数】

2

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