• Corrosion Science and Technology
• /
• 제11권5호
• /
• pp.165-172
• /
• 2012

The corrosion resistance of epoxy-coated carbon steel was evaluated. The carbon steel surface was subjected to different treatment methods such as steel grit blasting with different size, steel shot ball blasting and power tool treatment. To study the effect of the treatments, the topology of the treated surface was observed by optical 3D microscopy and a pull-off adhesion test was conducted. The corrosion resistance of the epoxy-coated carbon steel was further examined by electrochemical impedance spectroscopy (EIS) combined with hygrothermal cyclic testing. The results of EIS indicated that the epoxy-coated carbon steel treated with steel grit blasting showed an improved corrosion resistance compared to untreated epoxy-coated surfaces or surfaces subjected to shot ball blasting and power tool treatments.

• Journal of Welding and Joining
• /
• 제5권2호
• /
• pp.27-34
• /
• 1987

The characteristics of arc sprayed layer were studied with hardness test and microstructural observation. The erosion resistance of arc sprayed layer was also evaluated using a method of steel ball blasting test which was proposed in this study as a test method for measuring the erosion properties in the impact wear condition. By an impact of the molten droplets on the redeposited substrate, lamella structure was formed which contains laminated oxide layers, fissures, and porosities. As a result of mechanical tests, it was shown that the sprayed specimen showed higher hardness than the substrate, but it resulted in higher erosion rate than the substrate. The poor erosion property obtained with a sprayed coating was considered to be attributable to easy flaking off the the layers laminated with brittle oxide layers.

• 화약ㆍ발파
• /
• 제29권1호
• /
• pp.41-47
• /
• 2011

발파에 의한 암반손상영역을 평가하고 암반 파쇄도를 제어하기 위해서는 장약실 내 발생하는 폭발압력에 관한 정보는 중요하다. 이를 위하여 본 연구에서는 철, 알루미늄, 아크릴 재질의 센서에 대한 낙추 충격 시험으로부터 동적 변형률 신호를 측정하여 센서의 동적 응답 특성을 분석하였다. 철재 센서의 경우 충격하중에 가장 적은 변형률 출력 값을 보였으며 센서길이에 대한 출력 값의 변화는 적게 나타났다. 철제 센서를 뇌관의 충격하중 측정에 적용하였다.

• 대한기계학회논문집A
• /
• 제22권3호
• /
• pp.529-539
• /
• 1998

A quantitative study of impact damage of ${Al_2}}O_3}-TiO_2$ plasma coated soda-lime glasses was carried out and compared with that of the uncoated smooth glass specimen. The shape of cracks by the impact of steel ball was observed by stereo-microscope and the decrease of the bending strength due to the impact of steel ball was measured through the 4-point bending test. At the low velocity, cone cracks were occurred. As the impact velocity increases, initial lateral cracks were propagated on the slanting surface of a cone crack, and radial cracks were generated at the crushed site. When the impact velocity of steel ball exceeds the critical velocity, the contact site of specimen was crushed due to plastic deformation and then radial and lateral cracks were largely grown. Crack length of coated specimens was smaller than that of uncoated smooth specimen due to the effect of coating layer on the substrate surface. According to impact velocity, the bending strength of coated specimens had no significant difference, compared with that of the uncoated smooth specimen. But this represents that the bending strength of coated specimens was increased, considering the effect of sand blasting damage which was performed to increase the adhesion force of coating layer.