×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

More chemistry than metallurgy

More chemistry than metallurgy

More chemistry than metallurgy

(OP)
Here's a question for those folks who deal with chemistry on a daily basis.  I personally haven't dealt with it since my first year of college, so I'm a bit rusty.

I'm currently making a solution of magnesium hydroxide and isopropyl alcohol.  The concentration of Mg(OH)2 in solution is about 0.2 g/cc.  I'm coating parts with this, then putting them in a high heat furnace (2500+°F) under atmosphere.

Looking at the chemical formualas, I figure the magnesium hydroxide will reduce to MgO + H2O, with water vapor going up the stack and the MgO remaining on the parts.  Isopropyl alcohol (C3H8O) is more of a question.  If the water pulls out of that one, I'm left with C3H6 + H20, again with the water vapor going up the stack.  Now, the C3H6 would be cyclopropane, a flammable gas and old school anisthetic.  If this is the case, I'm guessing it would be an almost instantaneous ignition when it hit air, but because of the small quantity of it on the parts, the flame would also be short-lived.  Right or wrong?

RE: More chemistry than metallurgy

What is the purpose of the coating?

In any case, I think you're on the right track. You'd be left with MgO, with the alcohol volatilising and burning, although you wouldn't expect to see much of a flame.

If the amount of air intake into the furnace is restricted, it's possible you might see some charring (carbon).

It might be possible for the alcohol to reduce the MgO to Mg metal, but I think this only would occur at very high temperatures (2000 C), and the Mg metal would quickly oxidize to MgO once in a normal atmosphere.

RE: More chemistry than metallurgy

(OP)
The purpose of the coating is to keep parts from sticking together.  I've seen it used in heat treating applications before, but never at this high of a temp.

I ended up running the test last night and it worked extremely well.  No problems with the furnace, and the layer of MgO left on the parts with the alcohol solution actually brushes off by hand.  In a water solution it seems to embed more into the parts.

Thanks for the input.  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources