EPDM rubber(EPDM 고무); Thermal oxidative aging(열 및 산소 노화); Electro-chemical degradation(전기화학적 노화); Micro-hardness(미크로경도); Failure strain(파괴 신장률)
대한기계학회 2005년도 재료 및 파괴부문 추계학술대회 논문집, Page. 56 - 61
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.