Improving the Corrosion Resistance of the Rifle Parts by Electrodeposition Method

• Main Authors: SYU,JIAN-HUANG, 許建皇
• Other Authors: SHEU, HUNG-HUA
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/s3arfk

碩士 === 國防大學理工學院 === 化學工程碩士班 === 106 === This study is focus on the improvement of corrosion and wear resistance of rifle parts which electroplated different type of coatings such as Cr-C, Ni-P and Ni-B coatings. The mechanical properties, corrosion resistance, wear resistance and hydrophobicity of different coatings electrodeposited on various substrates are studied. The electrodeposited alloy coatings are used to improve various problems faced by current rifle parts, it is expected that the advanced surface treatment technology can be applied to the rifle equipment of the national army to increase its life and reliability . The results show that the 8620H steel and 420 stainless steel electroplated different coatings such as Cr-C, Ni-P and Ni-B coatings by using direct current deposition technology, the cracks and holes of various sizes appear in the Cr-C coating, and clear demarcation, and the surface of the Ni-based coating exhibits a relatively dense and even surface. The X-ray diffraction pattern shows that the Ni-B coating has a strong crystallinity, and the Ni-P plating belongs to the amorphous-like phase, the Cr-C coatings also present an amorphous phase. The contact angle measurement results can be observed that the surface hydrophobicity of the coated layer is significantally improved from substrate. The Cr-C coatings exhibited the best hydrophobicity, and the contact angle is up to 90∘. The results of mechanical property analysis and wear test showed that the Ni-B coating had the highest hardness and the lowest wear rate. The potentiodynamic polarization curves show that the corrosion current density of the Ni-B coatings electrodeposited on the 8620H steel is 2.2×10-6 A/cm2, and Cr-C coatings (chlorination system) electrodeposited on the 420 stainless steel part is 9.87×10-7 A/cm2. After 24 hours of salt spray test, the Ni-B coating still maintained more than 9 levels. The adhesion of the Ni-B coatings electroplated on the rifle parts is significantly improved due to the pre-processing that the rifle parts was used sandblasting process before electroplating and then electrodeposited at a higher current density.