Solomon-10/03 \corrected\ zaida

We use cookies to personalise content and ads, to provide social media features and to analyse traffic. We share info about use of our site with social media, ads and analytics partners. By continuing to browse you are agreeing to use of cookies. See details or close this message.

Page

/10

100%

Specifications	Solomon-10/03 \corrected\ zaida
Business section

WELDING RESEARCH OCTOBER 2003-S278 ABSTRACT. A high-temperature wetting balance was developed to provide infor- mation about

Specifications	Solomon-10/03 \corrected\ zaida
Suggested Link Details/Purchase
Content	WELDING RESEARCH OCTOBER 2003-S278 ABSTRACT. A high-temperature wetting balance was developed to provide infor- mation about the wetting force and its time dependence. The instrument and the development of the wetting force are dis- cussed. As example of the operation of this instrument, data are presented on the effects of grit blasting of IN718 on the wet- ting by AMS4777 (AWS BNi-2). The grit blasting was done with Al2O3, SiC, and a Ni-Cr-Fe alloy, and contrasted with me- chanical polishing. Grit blasting with Al2O3hinders subsequent wetting, but mechanical polishing of this grit-blasted surface restores the wettability. Grit blast- ing with the Ni-Cr-Fe alloy did not impede subsequent wetting. The effect of grit blasting with SiC was intermediate com- pared to that of the other two media. The measured time dependence of wetting stems from the time dependence of the chemical reactions (such as the dissolu- tion of oxides, the diffusion of braze con- stituents into the substrate, and the devel- opment of intermetallic compounds) that occur when a substrate reacts with a liquid braze. Introduction Wetting balances have been used for many years to characterize the wetting be- havior required for high-quality solder and brazed joints (Refs. 1–11). Most of these studies (Refs. 1–8) have been re- stricted to soldering because the commer- cial instruments do not operate at the ele- vated temperatures required for brazing, and they do not have the capability to op- erate in the inert environments that are generally required. This paper describes, in some detail, a simple wetting balance built for brazing studies. The classical in- terpretation of the wetting force that is measured by the balance is discussed, as are newer approaches that account for the chemical reactions that generally accom- pany the wetting of a metal by a liquid braze. These newer approaches explain the origin of the time-dependent behavior that is measured by the wetting balance. The problem of surface preparation via grit blasting is addressed with the wetting balance. Different grit blasting media and mechanical polishing are compared in order to determine their influence on sub- sequent wetting. Background The wetting force concept was devel- oped more than 100 years ago, and it ade- quately describes the physical wetting where chemical reactions do not play a role in wetting. More modern approaches to wetting take chemical reactions into ac- count and the influence of these on the ki- netics of wetting. The consideration of chemical reactions provides the means for explaining the origin of the time depen- dence of wetting that is measured by the wetting balance. This is an important con- sideration because one of the chief bene- fits to performing a wetting balance test is that it provides information on the wetting time, which is not obtained by the simple measurement of the wetting angle of a drop solidified onto a substrate. The wet- ting balance also provides quantitative data on the magnitude of the wetting force. The classical interpretation of the wet- ting force is that of a force developed by the balance of surface tensions acting on a liquid in contact with a solid surface. It as- sumes no chemical interaction of the liq- uid and the surface. The surface tension is defined as the change in free energy of a system as a function of the change in area of a boundary between phases. It has units of an energy/area or force/length. The equilibrium of the various forces/length that arise when phases are in contact can be treated by the simple mechanical bal- ance of forces shown in Fig. 1. The wetting angle, q, is defined by the balance of the forces/lengths developed between the solid, liquid, and the sur- rounding vapor where gSLis the interfacial tension between the liquid and the solid, and gSVand gLVare the surface tensions between the solid and the vapor and the liquid and the vapor, respectively. This balance of surface forces yields gSV= gSL+ (gLVcos q)(1) The difference between gSVand gSLhas been termed the wetting force, which rep- resents the difference in the energy/area (or the force per unit length) when a given area of solid, in contact with a vapor, is re- placed by a liquid. Correcting for the perimeter, L, to give a force F, rather than a force per unit length, gives F = L (gSV– gSL) =L gLVcos q(2) The magnitude of the wetting force is im- portant because this force controls capil- lary action (for instance, the force which draws the liquid braze into a gap between parallel plates) and is, along with the vis- cosity, the physical property that deter- mines the time required for wetting (Ref. 3). Equation 1 was developed from purely mechanical arguments by Young (Ref. 12) The High-Temperature Wetting Balance and the Influence of Grit Blasting on Brazing of IN718 Different grit blasting materials and mechanical polishing were compared to determine their influence on wetting BY H. D. SOLOMON, R. E. DELAIR, AND J. THYSSEN H. D. SOLOMON, R. E. DELAIR, and J. THYSSEN are with GE Global Research Center, Schenectady, N.Y. KEY WORDS Brazing Grit Blasting Wetting Balance Mechanical Polishing IN718
Navigation	Previous Page / Next Page
Suggested Link Details/Purchase

Following Datasheets	10-2003-VIANCO-s (10 pages) 10-2004-KIMAPONG-s (6 pages) 10-2004-MURUGANANTH-s (10 pages) 10-2004-WANG-s (5 pages) 10-2005-JENKINS-s (8 pages) 10-2005-POORHAYDARI-s (7 pages) 10-50TV_IPC-1752 (3 pages) 10-50TV_097_Rev_A (2 pages) 10-50TVC_IPC-1752 (3 pages) 10-50TVC_097_RevA (2 pages)
Check in e-portals	World-H-News Products Extensions Partners Automation Jet Parts
Sitemap Folder	group1 group2 group3 group4 group5 group6 group7 group8 group9 group10 group11 group12 group13 group14 group15 group16 group17 group18 group19 group20 group21 group22 group23 group24 group25 group26 group27 group28 group29 group30 group31 group32 group33 group34 group35 group36 group37 group38 group39 group40 group41 group42 group43 group44 group45 group46 group47 group48 group49 group50 group51 group52 group53 group54 group55 group56 group57 group58 group59 group60 group61 group62 group63 group64 group65 group66 group67 group68 group69 group70 group71 group72 group73 group74 group75 group76 group77 group78 group79 group80 group81 group82 group83 group84 group85 group86 group87 group88 group89 group90 group91 group92 group93 group94 group95 group96 group97 group98 group99 group100 Prewious Folder Next Folder