비정질 Cr-C 전착과 결정화 거동에 미치는 첨가제 효과 및 합금전착에 관한 연구

Title
비정질 Cr-C 전착과 결정화 거동에 미치는 첨가제 효과 및 합금전착에 관한 연구
Authors
변영민
Keywords
비정질crc전착과결정화거동에미치는첨가제효과및합금전착에관한연구
Issue Date
2016
Publisher
인하대학교
Abstract
◎ Amorphous Cr-C plating
Amorphous Cr-C plating layers were electrodeposited from a Chromium(Ⅲ) sulfate(Cr2(SO4)3・15H2O) bath containing formic acid. The effects of plating parameters such as pH and current density on composition, structure, morphology and corrosion behaviour of as-deposited coatings were investigated.
Results showed that the suitable current density for Cr–C plating layers are increased as the pH 2.5. Furthermore, by decreasing the pH, the effect of the cathode current efficiency and current density up to 10 % are increased. higher amount of carbon was introduced into the layers.
The Cr-C plating layers deposited as a whole consists of an amorphous chromium carbide locally crystalline chromium is present, the amorphous matrix portion by heat treatment of Cr(220), Cr(101) are BCC structure chrome crystal and chrome carbide with a Cr7C3, Cr23C6 and chromium oxide Cr2O5 in the form of crystallization.
The density of the plating layer is due to the crystallization portion is improved, the hardness and physical properties are affected depending on composition and compactness of the plating layer could lead to the conclusion.
Thus, a structure with a locally crystalline chromium particles on an amorphous Cr-C electroplated layer, could be concluded that the hardness and the corrosion resistance increases with the amorphous crystallization by heat treatment, a mixed organic chromium solution used in this study to solve the existing problems such as difficulty in controlling the plating solution will be able to replace the chromium plating.

◎ Amorphous Cr-P-C alloy plating
A mixture of Sodium Hypophosphite as a base Cr-C plating layers of a P source was obtained an amorphous Cr-P-C alloy plating layers, the amount of C that does not reacts to the current density in 3.3 at% and coated with a carboxyl group in the bath primary sodium phosphate has been confirmed that there is no interaction between the ligand Carbon free.
When the Cr-C in the creation phase of the first film to create a cause of lowering the current efficiency was, it was possible to suppress the influence of the Cr-P-C to obtain an effect to ease the spherical amorphous plating layers. That is, it is possible to prevent the Cr-P-C alloy plating layers surface cracks under the influence of P amorphous chromium carbide as the healing of the micro cracks to the small region to prevent the metal in direct contact with the corrosive medium has excellent corrosion resistance.
In conclusion, Cr-P-C alloy plating layer was increased corrosion resistance to mitigate the influence of the P in the amorphous spherical amorphous chromium carbide and chromium oxide generation.
◎ Amorphous Cr-C-Al2O3 composite plating
To study the effect of Al2O3 particles on corrosion behavior of Cr–C plating layers, substrates are electroplated in Cr-C baths with Al2O3. The results demonstrate that the introduction of Al2O3 particles eliminates the cracks within plating layers as a result of the reduction of internal stress. Therefore, the corrosion resistance of Cr–C–Al2O3 composite plating layers are better than that of Cr–C plating layers.
Heat treatment is also utilized to improve hardness of the Cr–C–Al2O3 composite plating layers. The hardness increases with heat treatment temperature. The highest hardness is found for Cr–C–Al2O3 composite coating annealed at 400 ℃ due to the precipitation of Cr23C6 and Al2O3 during the treatment.
According to Alumina (Al2O3), Cr-C plating layers could be concluded that the corrosion resistance and hardness increases effect is improved by the reduction of the corrosion resistance and the internal stress of the plated film amorphous Cr-C.
Description
제 1 장 서론 1
1.1 연구 배경 및 목적 1
1.2.연구 내용 및 구성 4
References 6
제 2 장 이론적 배경 7
2.1 크롬 도금 7
2.2 합금 도금 20
2.3 복합 도금 24
References 31
제 3 장 비정질 Cr-C 전착과 결정화 거동에 미치는 첨가제 효과 33
3.1 서론 33
3.2 실험 방법 36
3.3 결과 및 고찰 41
3.3.1 용액 안정화 41
3.3.2 공정 최적화 46
3.3.3 피막 형상 및 조성 51
3.3.4 열처리를 통한 피막 형상 및 조성 54
3.3.5 경도 및 내마모 특성 59
3.3.6 내식성 및 전기화학적 특성 64
3.4 결론 67
References 69
제 4 장 비정질 Cr-C 전착거동에 미치는 Phosphorous의 영향 71
4.1 서론 71
4.2 실험 방법 73
4.3 결과 및 고찰 78
4.3.1 Phosphorous 함량에 따른 도금욕의 영향 78
4.3.2 도금 피막의 형상 및 조성 84
4.3.3 도금 피막의 경도 및 내마모 특성 90
4.3.4 도금 피막의 전기화학적 특성 94
4.4 결론 96
References 98
제 5 장 비정질 Cr-C-Al2O3 복합도금에 있어서 Al2O3입자의 전착과 결정화에 관한 연구 100
5.1 서론 100
5.2 실험 방법 102
5.3 결과 및 고찰 108
5.3.1 Alumina 함량에 따른 도금욕의 영향 108
5.3.2 피막의 형상 및 조성 111
5.3.3 경도 및 내마모 특성 117
5.4 결론 120
References 121
제 6장 총괄 결론 123
URI
http://dspace.inha.ac.kr/handle/10505/35172
Appears in Collections:
Graduate School (일반대학원) > Theses(금속공학 석박사 학위논문)

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