대형실린더 내경의 정밀 6가 크롬도금 = Precision Hexavalent Chromium Plating on Inner Wall of a Large-sized Cylinder

다국어 초록 (Multilingual Abstract)

Requirements and service environments of a large sized cylinder on the hexavalent chromium coated inner wall were surveyed to develop an optimum electroplating condition for a long life-time. Crack density in the chromium layer showed a minimum value near the current density of 30～50A/dm2 and a maximum value at the solution temperature of 60℃. It is difficult to find micro-cracks in the layer coated above 80℃. The hardness of the layer increased with current density and decreased with temperature which was mainly related to residual stress. An artificial circulation made relatively uniform thickness, whereas, a natural circulation made more than two times thickness deviation on middle and bottom regions, which was enhanced with current density. The adhesion between matrix and coated layer significantly depended on surface treatment before electro-plating. The process with the order of electro-cleansing, electro-polishing in hydro-sulfuric and perchloric acids and chemical etching showed good adhesion. This resulted in finding an optimum electro-plating condition, setting up equipments for a large-sized cylinder.

목차 (Table of Contents)

• 목차 = ⅰ
• 그림 목차 = ⅲ
• 표 목차 = ⅳ
• （국문요약） = ⅴ
• 제1장 서론 = 1
• 2장 이론적배경 = 3
• 2.1 전처리 = 3
• 2.1.1 탈지(dogreasing, cleaning) = 5
• 2.1.2 산세(pichkling) = 10
• 2.1.3 전해연마 = 12
• 2.1.4 수세이론 = 12
• 2.2 크롬도금(chromium plating) = 13
• 2.3 수소취성(Hydrogen embrittleness) = 14
• 2.4 장축고압 실린더의 사용조건 = 16
• 제3장 실험방법 = 17
• 3.1 크롬 도금층의 기초물성 실험 = 17
• 3.2 공정에 따른 도금층의 밀착력 평가 실험 = 19
• 3.3 도금층의 성능 평가 실험 = 20
• 제4장 결과 및 고찰 = 21
• 4.1 크롬 도금층의 기초물성 평가 = 21
• 4.2 공정에 따른 도금층의 밀착력 평가 = 27
• 4.3 장축고압 실린더 내경 크롬도금공정 개발 결과 = 30
• 4.4 해외 내경 크롬도금공정과의 물성 비교 = 33
• 제5장 결론 = 36
• 참고문헌 = 37
• （Abstract） = 39