Talk:Heat sink

Scope of this article

I just wanted to comment that heat spreading/dissipating devices are by no means limited in application to microelectronics (or, to put it bluntly, PC microprocessors). I would try to improve this article's scope myself, but my focus lies elsewhere right now. This is merely a suggestion for anybody who might decide to improve the article. -- uberpenguin 20:06, 11 March 2006 (UTC)

Yeah, you're absolutely right. In thermodynamics, the term is used to mean somewhere that heat can be transferred to. In engineering, things like engines, power plants, these all have heat sinks, for example a power plant might use a nearby lake as a 'heat sink'. I think the PC microprocessor usage probably came after all this, and is a fairly specific example. Brendanfox 08:02, 13 October 2006 (UTC)

Removed pending citation

It is claimed that some brands of thermal grease that are advertised as containing silver or silver oxide actually contain neither, most notably that of CompUSA.{{citeneeded}}

- 81.155.170.206 16:19, 15 March 2006 (UTC)

The most common filler in the thermal greases is aluminum oxide.

171.64.160.33 09:04, 31 March 2006 (UTC)

I nowikied the template so that this talk page does not show up in the articles lacking sources category. -- Kjkolb 18:42, 6 April 2006 (UTC)

Name?

Heatsink or heat sink? -- Frap 11:24, 21 May 2006 (UTC)

It's "heat sink" in my dictionary. --Charles Gaudette 00:37, 8 June 2006 (UTC)

Removed pending citation #2

"Aluminum has the significant advantage that it can be easily formed by extrusion, thus making complex cross-sections possible."

This doesn't ring true with me — copper versus aluminum — they are both very malleable metals. I further asked someone with aerospace materials management experience, and they called it bogus too. If it can be cited to a reliable source, then by all means, put it back in the article. --Charles Gaudette 01:45, 8 June 2006 (UTC)

Not sure whether this was the original authors source, but a source confirming that claim is Groover's Fundamentals of Modern Manufacturing, Third Edition, p419, which says "Aluminum is probably the most ideal metal for extrusion (hot and cold), and many commercial aluminum products are made by this process...", a few pages later on p424 as an example of extrusions ability to form complex cross-sections is a picture of an aluminum heat sink. Brendanfox 23:46, 18 November 2006 (UTC)

I still have a problem with "significant advantage"; for instance extruded copper wire, and the tools and art of the Bronze Age. Does anyone have the ISBN for that book? --Charles Gaudette 01:24, 19 November 2006 (UTC)

The ISBN is 0-471-74485-9 [1]. The book also mentions "copper, magnesium, zinc, tin and their alloys" as typical metals used in extrusion, but it does seem to draw attention to aluminum as being "the most ideal". Unfortunately it doesn't give any particular reason for this. We could change the wording, tone it down a bit, but the basis of the claim (i.e. that aluminum extrudes better than copper) appears to be valid. Brendanfox 02:00, 19 November 2006 (UTC)

(First off, understand I am not fighting against you, just trying to work our way to a better "Heat sink" article.) Even if aluminum is easier to extrude, the underlying thrust implies that aluminum heat sinks are a cheaper manufacturing process (I'll give aluminum a raw materials cost lower than copper). Thanks for the ISBN. I'll have to do some research to catch-up to you, ... American Metals Association, hmm... --Charles Gaudette 19:04, 20 November 2006 (UTC)

No probs. You might also be interested in the graph from slide 47 of this: [2] - Brendanfox 04:01, 21 November 2006 (UTC)

The heat sinks cited are widely used with CPUs. But heat sinks in the form of flat plates are used with printed circuit boards. These are also called "cold plates" and "thermal planes". Heat spreaders are also closely related to heat sinks.

I suggest that the title be changed to "Heat Sinks and Heat Spreaders".

In addition to to copper and aluminum, other traditional heat sink materials include copper/tungsten, copper molybdenum and copper-Invar-copper.

In recent years, there have been important new heat sink materials, including aluminum particle-reinforced aluminum (Al/SiC), carbon fiber-reinforced aluminum, highly-oriented pyrolytic graphite, natural graphite, and diamond particle-reinforced silicon carbide, among others. The latter has been used in IBM servers. CarlZweben 22:18, 5 March 2007 (UTC) CarlZweben

Two considerations for improving article

First, consider noting that the term "heat sink" is a misnomer and that this expression is not found in heat transfer textbooks. A heat sink is a collection of extended fin surfaces (Hot Air Rises and Heat Sinks, Kordyban). Second, consider distinguishing between bonded fin heat sinks and extruded fins, augmented bonded fin heat sinks, etc.

P.K., August 6, 2007

Heat Sink Color

I have heard that Black Heat Sinks work better that non anodized or painted. Yet, I can't find conclusive evidence either way.

I suspect that there has been a misunderstanding of black bodies being ideal sources of thermal radiation. I think that in reality, the ideal source property describes the lack of environmental interference when making measurements.

The Anodize article does state that anodized aluminum has lower thermal conductivity than plain aluminum. Anodized aluminum would be protected from corrosion, which may be more detrimental.

Does anyone have a source with the answer?

Here is what I have found so far: From http://www.radianheatsinks.com/support/faqs.html

  How does the color of a heat sink impact its thermal performance?
  In natural convection a black or dark colored heatsink will perform 3% to 8% better
  than an aluminum heatsink in its natural silverish color. This is due to the fact
  that dark colors radiate heat more efficiently.
  
  In forced air applications, surface color does not increase a heat sink's performance
  due to the increase in convection. The color would provide cosmetic benefits only.

From http://www.globalwinusa.com/faqs/heatsink/color.html

  Does heatsink color affect heat dissipation?
  
  Black is the best thermal body in terms of being a absorber or emitter. Let's assume
  a vacuum situation, if the surface "A" of a black heatsink is totally covered at T1
  (temperature 1) by another black body at T2 (temperature 2), the black heatsink would
  get the energy reflected from another black body at reflection energy Ad(T14-T24) that
  we call "Stefan-Boltzmann" law of thermal radiation, here refers to Stefan Boltzmann
  Constant, it is 5.6697 x 10-8 w/m2?K4. Therefore if based on above, T1 is the
  temperature obtained from the black heatsink onto CPU, T2 is the ambient temperature
  around CPU. So if T14-T24 is a positive value, we know black is the best heat
  dissipation transistor since there is no thermal source around CPU inside PC case.

From http://www.bcae1.com/heatsink.htm

  Do not paint a heat sink. Most heat sinks are anodized aluminum. Painting a heat sink
  (especially if it's a thick coat of paint) is like putting a blanket on the amplifier.
  If you absolutely must paint the heat sink, use the lightest, thinnest coat of paint possible.

Thanks,

Eet 1024 20:59, 13 November 2007 (UTC)

Black does radiate better than other colors. I remember doing experiments on this in my undergrad degree. However color is not the only concern here. Paint usually is a poor heat conductor (especially household paints, this is why there are special heat sink paints), especially compared to metals, and therefore painting a heat sink using regular paints actually hinder heat dissipation. You enhance radiative dissipation (due to blackbody radiation), but hamper convective dissipation (due to air flow). Using very thin layers of paint means you get the full benefits of having a black color, and minimizes that harm you do to convective dissipation. I hope that clarifies. Headbomb {ταλκ – WP Physics: PotW} 13:37, 10 July 2008 (UTC)

I think the websites are saying other things equal black is better, which of course makes sense since black radiates more (although what matters is being black in the infrared, which is far from the same thing as being visibly black). But if the way you get it to be black is by adding a layer of paint that harms the thermal conductivity, it's not worth it; radiation is usually a very small proportion of heat transfer. The radiationsink website is basically saying that in natural convection heat sinks, radiation is a small (~10%) contribution to heat transfer, whereas in forced-air heat sinks, it's an utterly negligible contribution.