Prapassorn Numkiatsakul , Tonghun Lee , Kenneth S. Kim , Waltraud M. Kriven
{"title":"Enhancing oxidation resistance of silicon nitride using a Ca2+ stabilizer","authors":"Prapassorn Numkiatsakul , Tonghun Lee , Kenneth S. Kim , Waltraud M. Kriven","doi":"10.1016/j.jeurceramsoc.2024.116977","DOIUrl":null,"url":null,"abstract":"<div><div>Silicon nitrides are widely used in ceramic heaters for combustion engines due to their high strength and wear resistance. However, their poor oxidation resistance at elevated temperatures limits their reliability. Oxidation products, such as silica and intermediate compounds from sintering additives, often suffer from microcracks due to phase transformation and volume expansion mismatch during thermo-mechanical cycles. Use of cation dopants to chemically stabilize the transformation of the oxidation front is proposed. This study investigated the effect of Ca<sup>2+</sup> treatment on Si<sub>3</sub>N<sub>4</sub> with MgO and Y<sub>2</sub>O<sub>3</sub> sintering aids. The Si<sub>3</sub>N<sub>4</sub> samples were coated with CaO and the phase composition, microstructure, and chemical distribution of the oxidation products were analyzed using XRD, SEM, TEM, STEM, and EDS. The oxidation coupon tests revealed that the CaO coating effectively protected Si<sub>3</sub>N<sub>4</sub> from oxidation at 1300 ºC for 40 h. Moreover, the microstructural analysis showed that CaO coating created more favorable microstructures which reduced oxidation reactions.</div></div>","PeriodicalId":17408,"journal":{"name":"Journal of The European Ceramic Society","volume":"45 3","pages":"Article 116977"},"PeriodicalIF":5.8000,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of The European Ceramic Society","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0955221924008501","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, CERAMICS","Score":null,"Total":0}
引用次数: 0
Abstract
Silicon nitrides are widely used in ceramic heaters for combustion engines due to their high strength and wear resistance. However, their poor oxidation resistance at elevated temperatures limits their reliability. Oxidation products, such as silica and intermediate compounds from sintering additives, often suffer from microcracks due to phase transformation and volume expansion mismatch during thermo-mechanical cycles. Use of cation dopants to chemically stabilize the transformation of the oxidation front is proposed. This study investigated the effect of Ca2+ treatment on Si3N4 with MgO and Y2O3 sintering aids. The Si3N4 samples were coated with CaO and the phase composition, microstructure, and chemical distribution of the oxidation products were analyzed using XRD, SEM, TEM, STEM, and EDS. The oxidation coupon tests revealed that the CaO coating effectively protected Si3N4 from oxidation at 1300 ºC for 40 h. Moreover, the microstructural analysis showed that CaO coating created more favorable microstructures which reduced oxidation reactions.
期刊介绍:
The Journal of the European Ceramic Society publishes the results of original research and reviews relating to ceramic materials. Papers of either an experimental or theoretical character will be welcomed on a fully international basis. The emphasis is on novel generic science concerning the relationships between processing, microstructure and properties of polycrystalline ceramics consolidated at high temperature. Papers may relate to any of the conventional categories of ceramic: structural, functional, traditional or composite. The central objective is to sustain a high standard of research quality by means of appropriate reviewing procedures.