자동차 냉각기 호스용 고무의 노화특성 평가

Abstract

Coolant rubber hoses for automobile radiators can be degraded and thus failed due to the influence of contacting stresses of air and coolant liquid under the thermal and mechanical loadings. In this study, for the EPDM rubber conventionally used as a radiator hose material the aging behavior of the skin due to thermo-oxidative and electro-chemical stress was evaluated. Through the thermo-oxidative aging test, it was found that the surface hardness, IRHD of the rubber increased with a considerable reduction of failure strain. On account of the penetration of coolant liquid into the skin the weight of rubber specimens degraded by the ECD test increased, whereas their failure strain and IRHD hardness decreased largely. The penetration of coolant liquid into the specimen caused some changes in inner structure and micro hardness distribution of the rubbers.