สมบัติการเรืองแสงและความต้านทานการหมองของโลหะทองแดงที่เติมสารเรืองแสงชนิดสตรอนเซียมอะลูมิเนต

Abstract

The purpose of this study is to examine what happened once strontium aluminate (SrAl2O4) powder was mixed with copper (Cu) powder to enhance a phosphorescence and tarnish resistance properties of the samples. The samples were fabricated by using the compression molding technique and then sintered in argon atmosphere. Phosphorescence, hardness, microstructure, tarnish resistance and XRD were studied. In the process of the compression molding, the 4 samples of 100, 90, 80 and 70 percent by weight of copper powder, were mixed with 0, 10, 20 and 30 percent by weight of strontium aluminate, and called chronologically sample A (Cu100), B (Cu90), C (Cu80) and D (Cu70). Polyvinyl alcohol (PVA) was used as a binder and mixed with copper and strontium aluminate powder to produce the green specimens using a hydraulic machine. Then, the green samples were sintered at 900 °C for one hour. Consequently, PVA was eliminated and the samples became denser. After Vickers hardness testing, it was found that the hardness of sample A (30.5 HV) is higher than that of sample B (12.84 HV). Furthermore, sample B, C and D containing strontium aluminate were phosphorescent under ultraviolet at 517 nm. Sample D (Cu70) with the largest amount of strontium aluminate has higher phosphorescence than sample B(Cu90). In sulfur atmosphere, the tarnish resistance was found to be improved when strontium aluminate was added into copper. The color changing of sample A(Cu100), which has no strontium aluminate, was higher than that of sample B, C and D. Sample D(Cu70), containing the highest amount of strontium aluminate, has the least color changing on its surface resulting in the resistance in tarnishing. The analysis of composition of the samples with strontium aluminate addition in several ratios could be 2 types of oxide compounds as follows: strontium aluminate oxide, SrAl4O7 and tetra strontium tetra deca aluminum oxide (SrO)4(Al2O3)7.