Different quench vacuum pressure and PVD improve corrosion resistance of LED mold steel

• Main Author: 顏廷軒
• Other Authors: 才有益
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/16630545802870179790

碩士 === 高苑科技大學 === 電子工程研究所 === 104 === This research is aimed to discuss making the SUS440C martensite stainless steel of LED dies through different effects such as microstructure, hardness corrosion, different nitrogen gas quenching cooling pressure, PVD, and etc. Experimental samples were used 1100oC austenitizing to hold temperature, and they were respectively picked 4 Bar, 6 Bar and 8 Bar three different cooling gas quenching pressure. Then, they were tempered three hours under temperature of 480 oC twice and cooled at 150 oC. Next, 8 Bar cooling hardened steel material was sputtered with TiCN and CrN. Last, we do cyclic polarization curve capacity analysis by using electrochemistry test, and then use SEM and EDS for corrosion samples to undergo the surface characterization. The experiment result indicates that the hardness of the material increases effectively with the elevation of cooling pressure; however, enhancing the cooling pressure doesn’t cause evident difference on couple organization. The cyclic polarization curve diagram result indicates that the probability of corrosion decreases if cooling pressure increases. Furthermore, the results of SEM and EDS show that surface pitting corrosion product appears the most evidently under the pressure of 4 Bar and 6 Bar. The result of the cyclic polarization curve diagram of sputtering with TiCN and CrN PVD film reveals that the corrosion resistance effectively increases whether being coated by TiCN or CrN; moreover, the more the surface of the coating CrN breaks the severer it is. By observing the cross sections of TiCN and CrN holes with SEM further, we can see that coating layers cave and they are continually penetrated by chloride ions down to the substrate to cause the pitting behavior. Further, by measuring pitting depths, if the depth of CrN is deeper, the corrosion situation is serious than that of TiCN.