Ferric chloride etchants

Ferric chloride etchant. Ocean State Electronics or other supplier. Ocean State Electronics ER-21. 

Ocean State Electronics - Printed circuit board, ferric chloride etchant, trays, tongs. 

Tin Plating. Thin tin deposits (0.0002 in) are used to make SMOBC boards where the tin etch resist is stripped after etching. Alkahne ammonia etchants are usually favored. Other etchants, such as sulfuric acid-hydrogen peroxide and ammonium persulfate-phosphoric acid, have been especially formulated for bright tin. Tin plating (directly over barrier layers of nickel or tin/nickel) has been used because of its optimum solderabihty. Cupric and ferric chloride etchants attack tin and are not used. 

Ferric chloride solutions are used as etchants for copper, copper alloys, Ni/Fe alloys, and steel in PC applications, electronics, photoengraving arts, and metal finishing. Current use of ferric chloride etchant in printed wiring fabrication is extremely limited in the United States because of costly disposal of the copper-containing etchant, and the much better commercial support for ammoniacal and cupric chloride etchants. There is still considerable use for alloy etching and photochemical machining applications. 

Copper etchants do not directly influence the electroless plating process, but are used merely to remove unwanted copper, and should not affect the deposit properties. The costs of waste treatment and disposal have led to disuse of throw-away systems such as chromic—sulfuric acid, ferric chloride, and ammonium persulfate. Newer types of regenerable etchants include cupric chloride, stabilized peroxide, and proprietary ammoniacal etchant baths. 

Although there is considerable evidence that chemical surface treatments improve the substrate bondability of stainless steels, there is no general agreement on which is the best. One etchant commonly used with stainless steels is an HNO3-HF mixture [128-131] others are chromic acid and ferric chloride/hydrochloric... 

Raw materials for PC board manufacture that contain metals include the following o Copper foil (encasing the board) o Etchants chromic acid, cupric chloride, ferric chloride o Catalysts stannous tin, palladium chloride o Electroless copper bath copper sulfate... 

When working with etchant solution, wear rubber gloves to keep the chemicals from contacting and staining your skin. Also, wear old clothes. The stain from the ferric chloride will ruin any clothing and the stain will not come out. Make sure you have plenty of rags around to wipe up spills, and follow all the safety recommendations on the package. Always pour the ferric chloride dry etchant powder into the water. Do not pour the water onto the ferric chloride. When you pour the ferric chloride into the water, do so slowly. Use distilled water for this solution. 

About /2 of ferric chloride at most is needed to etch both boards M is supposed to be enough to etch 200 square inches. Each board is about 80 square inches (8"x 10"), but more etchant may be required. Follow the directions that come with etchant for mixing. One pound of etchant requires 60 ounces of water, so for one or two boards, you need 15 ounces of distilled water for each M ... 

Ammonium chloride Ferric chloride Ferric chloride hexahydrate Potassium ferricyanide Triethylene diamine etchant ingredient, aluminum Ammonium sulfate Sodium chromate Sodium glucoheptonate Sodium nitrate Sodium silicofluoride etchant, ABS Chromic acid etchant, aluminum Ammonium bifluoride... 

In the continuous electrolytic regeneration of cupric chloride etchant the cuprous chloride is oxidised anodically in a cell while the cathode of the cell recovers the copper as a solid flake deposit. The cell, developed by the Electricity Research Council in the UK is divided by a membrane which limits the transport of copper ions, which are in fact complexed, probably mainly as CuCl3 . An economic analysis of the process realised a two year payback on the capital investment. In the case of alternative etchants, such as ferric chloride, continuous regeneration is also feasible. 

Ferric chloride can be used with screen ink, photoresist, and gold patterns, but it cannot be used with tin or tin/lead resists. However, ferric chloride is an attractive spray etchant because of its ease of use, holding capacity for copper, and ability to be used on an infrequent batch application basis. 

The composition of the etchant is mainly ferric chloride in water, with concentrations ranging from 28 to 42 percent by weight. Free acid is present because of the hydrolysis reaction and the need to maintain an acid environment. The natnral acidity is usually supplemented by additional amounts of HCl (up to 5 percent) to prevent formation of insoluble precipitates of ferric hydroxide. Commercial formulations for copper alloy etching are usually 36 Be, or approximately 4.0 Ib/gal FeCls, and may contain antifoam and wetting agents. Customary add operating HCl content is 1.5 to 2.0 percent. 

Precleaning for resist appUcation includes nonetch alkaline soak, water rinsing for 5 to 10 s in chromic-sulfuric acid, rinsing, and drying. Preferred etchants include ferric chloride (12 to 18° Baume), sodium hydroxide (5 to 10 percent), inhibited hydrochloric add, phosphoric acid mixtures, solutions of HCl and HF, and ferric chloride-hydrochloric add mixture. 

The methods previously described are adaptable to image transfer and etching of nickel-based materials. Etching uses ferric chloride (42° Baume) at about 100°E Other etchants include solutions made from one part nitric acid, one part hydrochloric add, and three parts water, or one part nitric add, four parts hydrochloric acid, and one part water. 

Etching High-resolution etchant (cupric chloride, ferric chloride)... 

The use of pcrsulphates is declining, partly due to their chemical instability and attack on tin-lead etch-resists (especially by ammonium persulphate). The oldest etchant is acidic ferric chloride, which is still used on a very small scale for batch processing and prototype development. The simplified reactions ate ... 

Cupric chloride in hydrochloride acid etchants are faster than the ferric chloride types and regeneration of the etchant is possible using chemical (H2O2 or CI2) or electrochemical treatments (see later). The overall etching process may be represented by ... 

Stainless steels Acid ferric chloride General stainless steel etchant. 

Hydrogen peroxide can be combined with vinegar and table salt to form a substitute for industrial chemicals such as ferric chloride, ammonium persulfate, or hydrochloric acid as a hobbyist s printed circuit board etchant. 

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