What is Trivalent Chromium?

What is Trivalent Chromium (Chrome) Process, which, at times, is also called Trivalent Coating Process? Well, lets take the words in stages.

Trivalent means having a valency of three. As for the word valency or valence, lets see what the Collins English Dictionary & Thesaurus says. It says that valency is a property of atoms or groups equal to the number of atoms of hydrogen that the atom or group could combine with or displace in forming compounds.

Now, what is Chromium? Basically speaking Chromium is a metallic element that is used to harden surfaces and it also causes the surfaces to become resistant to corrosion. Chromium is made naturally and it is also used in the making of stainless steel and other such materials. Therefore with that being said, let me condense it.

Trivalent Chromium Process is a combination of compounds used on surfaces that have the potential of rusting; thereby hardening the surface and helping it to become corrosion resistant.

What is Hexavalent Chromium?

One can not mention Trivalent Chromium without also mentioning Hexavalent Chromium. Hexavalent Chromium, which is primarily used by many companies, is slowly being replaced with Trivalent Chromium. This is mainly due to governmental (environmental) requirements in certain countries. Hexavalent Chromium performs the same function as Trivalent Chromium; that is, it protects products against rusting.

However, throughout the years, Hexavalent Chromium has proven to be detrimental to our health as well as to the environment.

Taken To Court

Erin Brockovich and Edward L. Masry brought a case against Pacific Gas & Electric Company in the United Stated Of America (USA). Erin Brockovich was not a lawyer she was a legal assistant at that time.

The case was based on Hexavalent Chromium that was found in the drinking water in the small town of Hinkley California. Pacific Gas & Electric Company were users of Hexavalent Chromium. The 1993 case was eventually settled in 1996 with the company making the largest settlement in the history of America in a direct action lawsuit.

In the year 2000, a movie entitled Erin Brockovich came out on the market. The movie is based on this incident.

Side Effects

It is said that one of the side effects of Hexavalent Chromium to the human body is that it causes lung cancer. A person who works directly and on a regular basis with Hexavalent Chromium is most likely to be adversely affected by it. Other side effects include skin irritation. Added to that the fumes that it disperses are dangerous to the environment.

Therefore it is with a sense of relief that Trivalent Chromium is now being used in certain parts of the world, instead of Hexavalent Chromium. Automobile giants such as DaimlerChrysler and Ford have taken several steps to replace the use of Hexavalent Chromium. The Ford Company has pointed out that it has stopped using Hexavalent Chromium on several of their parts.

Advantages of Using Trivalent Chromium

There are several advantages to using Trivalent Chromium. A few of them are it does not emit fumes, less heavy metal concentration dragout and it meets with the RoHS regulations.

Does not Emit

This is extremely important since it helps to reduce the health hazards and environmental harm that airborne chromium contains. When this airborne hazard comes in contact with the eyes, it causes a burning sensation. It damages the nasal tissues and it affects the throat with a "scratching" sensation. Overall these fumes are not pleasant to inhale. The workers and the environment will be a lot safer.

Less Heavy Metal Concentration

With trivalent chromium materials less time and money will be spent on waste management. Trivalent solutions also need less regular changing which can be very cost effective unlike hexavalant solutions that require frequent changing. In this case the environment and the company will be profiting.

RoHS

RoHS is the acronym for Restriction of Hazardous Substances. This is set up within the European Union. RoHS has brought out a directive concerning the use of Hexavalent Chromium. Although this is a European Union directive it still has a far-reaching effect for many countries around the world. An example of its global reach is that whatever passes through the European Union, due to trading for example, must be in line with its regulations.

The main purpose of RoHS is to keep to a minimum the hazardous materials that are entered into electronic products. The RoHS regulations had taken effect on the 1st July 2006. That is not to say that RoHS has band the use of Hexavalent Chromium, that is, in its entirety. No, it had not; it has simply placed some regulations "in the books" so to speak, concerning the using of it.

Disadvantages of Using Trivalent Chromium

Of trivalent passivates the main disadvantage is the range of colours that are available at present are not as great as the hexavalant colour range. Generally the corrosion resistance can be made to perform as well as hexavalent chrome by using various concentrations and seals.

More Chemicals Used

This speaks for itself. Since an extra coat will be needed, more chemicals will have to be used in the Trivalent Chromium process.

Cost More

It is expensive for a service provider to use the Trivalent Chromium system and to maintain it. The organic acid that is needed for Trivalent Chromium is more expensive compared to the hydrochloric and sulfuric acid that is used in Hexavalent Chromium. So ultimately, the consumer will feel the increase in their hip pockets.

What Are Its Uses?

Trivalent Chromium is used on electrical components, appliances, with the auto industry being the main user.