Study on fine lines and undercut suppression of printed circuit board prepared by electrolytic etching

Purpose The purpose of this paper is to study an electrolytic etching method to prepare fine lines on printed circuit board (PCB). And the influence of organics on the side corrosion protection of PCB fine lines during electrolytic etching is studied in detail. Design/methodology/approach In this paper, the etching factor of PCB fine lines produced by new method and the traditional method was analyzed by the metallographic microscope. In addition, field emission scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to study the inhibition of undercut of the four organometallic corrosion inhibitors with 2,5-dimercapto-1,3,4-thiadiazole, benzotriazole, l-phenylalanine and l-tryptophan in the electrolytic etching process. Findings The SEM results show that corrosion inhibitors can greatly inhibit undercut of PCB fine lines during electrolytic etching process. XPS results indicate that N and S atoms on corrosion inhibitors can form covalent bonds with copper during electrolytic etching process, which can be adsorbed on sidewall of PCB fine lines to form a dense protective film, thereby inhibiting undercut of PCB fine lines. Quantum chemical calculations show that four corrosion inhibitor molecules tend to be parallel to copper surface and adsorb on copper surface in an optimal form. COMSOL Multiphysics simulation revealed that there is a significant difference in the amount of corrosion inhibitor adsorbed on sidewall of the fine line and the etching area. Originality/value As a clean production technology, electrolytic etching method has a good development indicator for the production of high-quality fine lines in PCB industry in the future. And it is of great significance in saving resources and reducing environmental pollution.

An Optimized Nontoxic Electrolytic Etching Procedure for Fine Art Printmaking

In this National Endowment for the Arts funded project we wanted to find a way to provide artists with an innovative method for creative expression using electrolytic etching techniques that have long been used in the electronics and biotech industries. Using scientific methods the electrolytic etching process was improved and then compared side by side with copper etched in ferric chloride after analysis with an AFM. The optimized electrolytic etching method proved to be superior to classical acid etching in intaglio printmaking.

Identification of Carbides in Tool Steel by Selective Etching

This paper describes simple metallographic technique for selective etching of individual types of carbides (MC, M2C and M6C and M7C3) in tool steel. Electrolytic etching in chromic acid was used in order to reveal the MC carbides. Chemical etching in permanganate solution revealed the M2C and M6C carbides, while the electrolytic etching in the latter solution enabled to observe M7C3, M2C and M6C carbides. These techniques were demonstrated on an experimental niobium-containing tool steel prepared by powder metallurgy. The results confirm that the MC carbides are highly thermally stable, while the M2C carbides decompose during austenitizing at the temperature of 1050 °C and higher. The M7C3 carbides dissolve in the austenite significantly. This exact and simple observation of the carbides behaviour enables to describe the role of particular carbides on heat treatment behaviour and also to save the carbide-forming elements, where the important ones (tungsten, vanadium) are listed as critical raw materials and the others (chromium and molybdenum) are also strategic.

Corrosion behaviors of 316LN stainless steel joints brazed with Sn-plated silver filler metals

AgCuZnSn filler metals were prepared from the BAg34CuZnSn filler metal by a combinative process of brush plating and thermal diffusion, and the prepared filler metals were applied to the induction brazing of the 316LN stainless steel. The corrosion behaviors of the brazed joints was evaluated based on local corrosion analyses, where the morphology of the joints was analyzed by scanning electron microscopy (SEM) after immersion in a 3.5 wt.% NaCl aqueous solution and electrolytic etching in a 10 vol.% oxalic acid solution. The microstructure of the brazed joints with the Sn-plated filler mainly consisted of the Ag phase, Cu phase, CuZn phase, Cu5Zn8 phase, Cu[Formula: see text]Sn[Formula: see text] phase and Ag3Sn phase. The local corrosion analysis results indicated that galvanic corrosion occurred near the interface between the stainless steel base metal and the brazing seam. With increasing local corrosion time, the corrosion rates of both the brazing seam and the base metal first exhibited an increasing trend, followed by a decreasing trend, and the corrosion rate of the brazing seam was slightly greater than that of the base metal. The corrosion behaviors analysis indicated that the corrosion resistance of the brazing seam was reduced, and concave defects emerged after electrolytic etching for 90 s.

The ecological techniques and materials in artistic graphic art

In the paper, against the background of art and ecology associations, formerly and today, modern ecological techniques and materials used in artistic printmaking have been presented. The considerations were related to the culture of past centuries and searching for the threads of ecological thought in philosophy, religion or art. The development of ecological thinking in European art is traced from the Middle Ages to modern times. The trends, concepts and methods of environmental graphics are characterized in the context of development and research of these methods in the world and in Poland. The basic techniques of ecological intaglio (etching, soft varnish, aquatint, chipping, photopolymer techniques and electrolytic etching) are discussed. Alternative materials and procedures were proposed based on literature and authors’ own research. The advantages and benefits of using these techniques in ecological and workshop aspects were analyzed.