What is the best material to use? 2

[LocusIndustries]

We are designing a hand held medical tool. We need it to be corrosion proof, durable and lightweight. Stainless Steel works well, but it is too heavy. 6061 Aluminum is lightweight, but it is soft and not very durable. Can we treat or coat the aluminum to render it hard and durable, resistant to dents, like stainless? Strength is not an issue. Is there an aluminum or other lightweight material that can be heat treated to a very durable hardness?

 

[testy]

Have you explored the possibility of using titanium? I think you will find it is used extensively in the medical field. It has the properties you are looking for, the only downfall being it's degree of machineability.

 

[etch]

Im not too sure the spec of 6061, but if it containe magnesium it can be heat treated to increase its hardness.

 

[ornerynorsk]

We used to make 1000's of hydraulic valve bodies for medical positioning devices out of aluminum. We ran a test on teflon filled hard-coat anodizing, and found that we could even use this material on actuator rods. The process is cheap, attractive, and gives options for different colors and degree of polish. Just a side note (sorry testy!) titanium is nothing but a nightmare that will drive your costs through the roof, and in 90% of the cases I've encountered, the same results can be achieved with a different, more workable material. You could even explore a 40 to 50% glass fill nylon material. Good Luck!

 

[TVP]

There are a number of things you can do to improve the hardness and wear resistance of aluminum alloys such as 6061.

First, as mentioned previously by etch, 6061 can be heat treated (solution treatment followed by artificial aging) to the T6 temper. If you haven't already investigated this process, it will improve the strength and hardness considerably compared to the annealed state (O temper).

Next, wear resistance can be improved by several methods. Anodizing is extremely common for this alloy, and it imparts a hard, wear resistant, and corrosion resistant layer to the aluminum. You will want an "engineering hardcoat" which is much thicker than the "architectural" or other aesthetic types. More information can be obtained from the following references:

ASTM B 580 Standard Specification for Anodic Oxide Coatings on Aluminum available from ASTM at

http://www.astm.org/cgi-bin/SoftCar.../htdocs/astm.org/DATABASE.CART/PAGES/B580.htm

MIL-A-8625F Anodic Coatings for Aluminum and Aluminum Alloys available from

http://131.82.253.19/docimages/0000/58/77/8625F.PD6

Metalast website

http://www.metalast.com/index2.html

(click on The Technology then Research and then TECHspecs, Research Reports, or Technical Bulletins

Keronite website

http://www.keronite.com

Microplasmic website

http://www.microplasmic.com/

Other coatings such as chromium nitride, diamond-like coatings, hard (industrial) chromium plating, etc. may also be useful. Some good websites for more info include:

http://www.ionbond.com

http://www.balzers.com/

http://www.diamonex.com/

 

[usaidit]

TVP is right on target.
Only one thing he left out, is the fact that anodized alum is now a non-conductor of electrical curent if that is a factor in your application.

 

[BarryMartin]

Anodizing is used for a variety of purposes and special solutions are available. If the entire part is to be treated and you have many parts the a tank anodizer would be a good bet. If you only need part of the piece to be hardened and have a relatively small volume of parts, then selective anodizing might be suitable. This is done for parts for the aircraft industry. Some info on selective anodizing is available at

http://www.brushplating.com