트리에탄올아민을 錯化劑로 사용한 無電解니켈鍍金浴의 析出速度에 관한 研究

呂運寬(Yeo Woon Kwan) 한국표면공학회 1985 한국표면공학회지 Vol.18 No.4

훼로보론과 NaBF₄에 의한 鋼材의 浸硼硬化處理에 關하여

金文一(Moon-Il Kim),呂運寬(Woon-Kwan Yeo) 한국표면공학회 1975 한국표면공학회지 Vol.8 No.3

PCB제조용 무전해 동도금액에 대한 계면활성제의 영향

이홍기(Hong-Ki Lee),심미자(Mi-Ja Shim),김상욱(Sang-Wook Kim),여운관(Woon-Kwan Yeo),이주성(Ju-Seong Lee) 한국표면공학회 1993 한국표면공학회지 Vol.26 No.5

중성 아연 도금층의 물성에 관한 연구

呂運寬 홍익대학교 산업기술연구소 1999 産業技術 Vol.9 No.-

It has been known that the cyanide zinc bath has a pollution problem while the acidic zinc bath has poor throwing power in addition to the problem of equipment corrosion. This study has reviewed the physical and chemical properties of the electro deposit obtained from the neutral zinc bath containing zinc chloride 15g/ℓ, potassium chloride 100g/ℓ, complexing agent(AN 404) 120g/ℓ, brightener #1 (ZN 402) 35㎖/ℓ, and brightener # 2 (ZN 403) 7㎖/ℓ. This study has obtained the following experimental results. 1) The bright electro plating deposits are obtained under widely varying operating conditions of the current density 0.5∼20A/dm^2, and temperature 25℃∼40℃. 2) Ductility of the deposit obtained from the neutral bath is better than that from the acidic bath but poorer than that from the cyanide bath. 3) The deposits obtained from the cyanide bath have the preferred orientation of (101) and (100), and (110). 4) In the neutral hath the preferred orientation of (11) gets stronger as the current density increases. At the bath temperature of 60℃, the preferred orientation of (11) disappears and that of (100) becomes stronger, and the deposits with low current density at high temperatures have the preffered orientation of (101) and (100). which is similar to deposit obtained from the cyanide bath. 5) In the salt spray test, white corrosion marks appear in the deposit obtained from the neutral, acidic, and cyanide bath in 6, 4, and 7 hours, respectively, but the deposits obtained from the neutral bath with a low current density and at high temperature show good resistance to corrosion, which is similar to the deposits obtained from the cyanide bath.

크롬도금에서 전류 분포 균일화에 관한 연구

呂運寬 홍익대학교 산업기술연구소 1997 産業技術 Vol.7 No.-

In order to find a solution to make it uniform the current distribution situation of chromium plating solution we have found the following results; which to use and inspect a divided cathode panel in Hull cell. When using the current shield it is more effective to position the current shield closely by the place which requires to shield the current. When using the auxiliarly anode it is more effective to place the current shield near the place of low current density. Current distribution by the bipolar electrode can not be controlled without causing bipolar phenomena in Sargent chromium plating solution. The current distribution in Hull cell is rather uniform than that in copper sulfate plating solution. We have found that the reason for the throwing power's weakness is caused by the poor current efficiency and poor covering power in the place of low current density.

중성아연 도금욕에서 착화제의 영향

呂運寬,鄭光龍 홍익대학교 산업기술연구소 1998 産業技術 Vol.8 No.-

This study was examined on the effect of complexing agents for the throwing power, current efficiency and morphology of electrodeposited layer in the neutral zinc plating bath containing ZnCl_2(40g/l), KCI(100g/l), H_3Bo_3(60g/l), and complexing agent (90g/l) In terms of enlarging the bright range of plating EDTA(4Na salt) added bath was the best and sodium gluconate added bath was also good. However sodium gluconate added bath has a better result for the throwing power and current efficiency than EDTA added bath has. Throwing power is inclined to decrease slightly in both baths according to a rise in temperature and increase according to the current density and pH. In both bath, current efficiency decreases according to a rise current density and decreases slightly according to a rise in pH but increases according to a rise in temperature. Cross sectional micrograph of electrodeposited layer appeared not in the lamellar or columnar texture but in the very fine testure. The morphology of elecrodeposited surface was almost the same as obtained from Zine cyanide pl

Thermit법에 의한 저탄소 Fe-Mo, Fe-W의 제조 조건에 관한 연구

呂運寬 홍익대학교 산업기술연구소 1994 産業技術 Vol.4 No.-

The mixing ratio of reducing agents and reasenable operation condition of making low carbon Fe-Mo and Fe-W were examined. In addition hear of formation on the Thermit reaction and hear capacity of products were inverstigated. Compared with hear of formation when reduction Fe-Mo and Fe-W with Al that with Si is only 45% and 43% and hear capacity of reduced products from Si is more then that of Al. Reduction velocity is controlled by amount of Al. Si and CaO.

고균일 전착성 황산구리도금욕의 전류분포에 관한 연구

呂運寬 홍익대학교 산업기술연구소 1995 産業技術 Vol.5 No.-

The state of current distribution was compared and examined using the cathode electrode divided into 5 sections in Hull cell and typical tank for the study of high through copper sulfate plating bath. Deviation of current distribution of high through copper sulfate plating bath in Hull cell is uniform by the ratio 2.0:1 of high current density section and low current density section and that of bright copper sulfate plating bath is 5 times as big as in the ratio of 9.6.1 but that of both plating baths in typical tank are found to be uniform. The effect of uniformity of current distribution remarkably appeared according to increase of concentration of sulfuric acid but scarcely appeared by changing concentraion of copper sulfate.

金屬類의 海底腐蝕에 관한 硏究

白英男,呂運寬 慶熙大學校 1980 論文集 Vol.10 No.-

This study aims at corrosion phenomena of metallic assets in order to preserve the closest original shape by applying scientific treatment of delivered metallic assets from the bottom of the sea Steel assets seems to be in a complex corrosion environment by showing corrosion excretion of organic substances, such as shellfish, marine microorganims on the surface and corrosion from silt and galvanic cell by potential difference between heterogeneous metals. Silver assets seem to be affected by corrosion of organic corrosive substances, such as algae, excreta from shellfish and H_2S gas and such corrosion appears to be noticeable when such substance are placed in the silver container. Bronze assets tends to form progressive stains, copper chloride, generally called bronze ailment by reaction Cl^- ion the sea water.

低炭素-W-Ni-Cr-Mo合金鋼의 熱處理에 關한 硏究

崔壯宇,呂運寬,南勝義,韓允熙,朴明果 弘益大學校 1973 弘大論叢 Vol.5 No.-

Ordnance scrap materials such as tank body parts consisting of low carbon alloy steel (0.12% C, 0.8%, W, 0.5% Cr, 1.3% Ni, 0.3% Mo.) have great tougheess and low hardness. The maximum attainable hardness of any steel depends on carbon content. Therefore, the experiment thas been casried out to study a hardening process of this alloy in application for manufacturing the high speed rotary shearing tool or similar tools. The important results obtained from the study are summerized as follows: 1. Under the pack carburizing process at 925℃ for 10 hrs. we could take the case depth 2.5mm. By the quenching process the hardness of this alloy steel has increased up to HRC 64. 2. The case depth and carbon content could be increased by the carburizing time. When the process time took over 10hrs, the carbon content of the surface reached to that of the hypereudectoid steel (0.9 C). In this case, the structure of case surcture of case surface became a rough net work of brittle cementite. 3. The Quenching process must be done by two step quenching to control the rough austnite structure. The optimum quenching conditin was obtained with the first quenching temperature at 900℃ and the scend quenching temperatare at 770℃.