That is not true. I don't believe hydrazine compounds have been used in
electronics fluxes made by any reliable manufacturer for at least 30 or
more years. There are two chemistries commonly used for brominated flux
activators: amino acid hydrobromides and amine hydrobromides, with many
variants. One popular one for both HAL and WS fluxes is glutamic acid
hydrobromide. Even RMA fluxes may contain amine hydrobromides, such as
ethylenediamine hydrobromide. The advantage of these is that you need
far less activator for a given activity, compared to their hydrochloride
analogues. This can make solubility issues easier, in both the flux
itself and in cleaning the residues.
Even Manko's 1st edition Solders and Soldering (1964) does not list
hydrazine halides but does list "aniline hydrochloride, glutamic
hydrochloride and bromide derivatives of palmitic acid". For the record,
I have used aniline phosphate for soldering Nichrome V wire and I
recount an amusing episode making the stuff in the Preface of my book!
That was in 1957, over half a century ago!!!!! Dammit, that makes me
feel old!
Brian
Brian
R Sedlak wrote:
> Re:�� Hydrobromic Acid
>
> Most fluxes which list Hydrobromic acid as an ingredient also contain Hydrazine.�� The reason why Hydrobromic is used is that it is one of the few acids which forms soluble salts with Hydrazine.��� When the Hydrobromic and Hydrazine are mixed, a compound called Hydrazine Hydrobromide is formed, and this compound is not a known carcinogen, so if it is present at levels less than 1%, it does not need to be listed on the MSDS.
>
> I mention this because at temperature, the Hydrazine Hydrobromide breaks down, and volatilizes, and is not something I would recommend inhaling too much of.�� Although, you can emulate a former US president, who "did not inhale"!
>
> Rudy Sedlak
> RD Chemical Company
>
> --- On Fri, 9/18/09, Paul Edwards <[log in to unmask]> wrote:
>
> From: Paul Edwards <[log in to unmask]>
> Subject: Re: [TN] Black Pad
> To: [log in to unmask]
> Date: Friday, September 18, 2009, 9:38 AM
>
> This effect can also appear if the PCBs have been baked...
>
> Then good luck soldering to the PCBs with anything other than hydrobromic acid...
>
> Paul
>
> Paul Edwards
>
> Surface Art Engineering
>
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
> Sent: Friday, September 18, 2009 6:54 AM
> To: [log in to unmask]
> Subject: Re: [TN] Black Pad
>
> Hi Rudy - actually, if the copper and tin form an intermetallic phase
> during your first pass thru the reflow oven (which they should) then you
> would have solderability issues during subsequent soldering operations.
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]
>
>
>
>
> R Sedlak <[log in to unmask]>
> Sent by: TechNet <[log in to unmask]>
> 09/18/2009 08:44 AM
> Please respond to
> TechNet E-Mail Forum <[log in to unmask]>; Please respond to
> R Sedlak <[log in to unmask]>
>
>
> To
> [log in to unmask]
> cc
>
> Subject
> Re: [TN] Black Pad
>
>
>
>
>
>
> Linda:
> Actually, it is quite possible to get black immersion Tin.���It comes from
> running a bath with an excess of Cupric Copper in it.���I wrote a article
> on how to monitor Cupric Copper in immersion Tin baths to avoid this in a
> recent PCD&F magazine.
>
> The black color should not affect solderability, as it is actually
> immersion Copper on top of the Tin.
> Rudy Sedlak
> RD Chemical Company
>
> --- On Fri, 9/18/09, Linda Langley <[log in to unmask]> wrote:
>
> From: Linda Langley <[log in to unmask]>
> Subject: [TN] Black Pad
> To: [log in to unmask]
> Date: Friday, September 18, 2009, 3:12 AM
>
> I know we have had this subject many times before so I did go to the
> archives and still can't find an answer. My question, is Black Pad only
> associated with ENIG? Is it possible with immersion Tin?
>
>
>
> Linda Langley CIT
>
> Training Specialist
>
> Jabil Circuit
>
> 248-292-6176
>
>
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