Platinum-Based Alloys: Investigation of the Effect of Impurities Content on Creep Rate, Rupture Time and Relative Elongation at High Temperatures

Abstract

This paper presents the results of research of the effect of impurities content on high-temperature resistance of selected platinum alloys. Alloys of following systems were investigated: Pt-Rh, Pt-Rh-Pd, Pt-Rh-Pd-Ru and Pt-Rh-Pd-Ir-Au. Universal device for tensile testing of materials at high temperatures was used for examination. Investigations were carried out in a temperature range of 1300-1400 °C, with a stress of 5 MPa. It was observed that an increase in content of impurities in tested alloys at high temperatures, and at stated conditions of stress, caused a noticeable increase in creep rate while reducing rupture time and relative elongation. Experimental results confirmed that probability of brittle fracture decreases with decreasing impurity content in the alloys. Binary and multicomponent alloys of Pt-Rh, Pt-Pd-Rh, Pt-Rh-Pd-Ru and Pt-Rh-Pd-Ir-Au systems are primarily used in conditions of high temperature, and accordingly, presented results contribute to a better understanding of their behavior in such working conditions.

Total risk of a false decision on conformity of an alloy due to measurement uncertainty and correlation of test results

“…The standard [14] sets the lower and upper specification (tolerance [7]) limits, T Li and T Ui , of contents c i of the four following components in PtRh 92.5-7. Limitation of the impurities' contents, which assure the alloy purity, prevents a change of its microstructure influencing high-temperature resistance, catalytic and other alloy properties [16,17]. By agreement with a consumer, the number of impurities under control (each with its separate upper specification limit) can be increased [14], but for simplicity, this is not discussed further in the current work.…”

A Comparative Study about Accuracy Levels of Resistance Temperature Detectors RTDs Composed of Platinum, Copper, and Nickel

“…This metal is widely used because it has highest temperature coefficient of resistance TCR [16]. Platinum holds many features such as high malleability, high corrosion resistance, high ductility, stable electric properties, chemical stability, and it has negligible reactivity with surrounding factors [21]. These features increase the accuracy level and it can be used in high temperature RTDs sensors.…”

“…The analysis from [16,[20][21][22][23][24][25][26] in above subsections (5.2., 5.3., and 5.4.) will summarized as in table 1 is showing the comparison between some features of three metals which have effects on the accuracy level of RTDs.…”

“…The analysis from [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] in above section (5. Methods and materials) will summarized as in table 2.…”