Evaporation apparatus

The SiO, usually a dark brown powder, is used for the evaporation source because it is a very easily evaporated oxide using conventional resistive heating. In the case of Si02, high temperature heating by the electron beam, for example, is indispensable, and is not suitable for TFT array substrates due to the damage by recoiling electrons. 

As the evaporation angle must be controlled accurately, the angle difference at both edges of the substrate must be less than several degrees. Thus the distance between the substrate and the linearly aligned evaporation boats must be rather large. Due to this geometrical requirement, evaporation chambers of sufficient size are necessary. 

Moreover, in-plane uniformity of the film thickness has to be carefully controlled for device manufacturing which means taking extreme care over the evaporation control of the boats, together with the charging amount and the temperature. Thus there are a lot of problems to be solved for handling large sized substrates of almost 1 m square and the continuous process required for the mass production. 

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Abdampf. evaporating exhaust-steam, -appa-ratf m. evaporating apparatus. 

Eindampfapparat, m. evaporating apparatus, eindampfen, v.i. become thickened by evaporation, boil down. 

Verdacht, m. suspicion, distrust, verdachtig, a. suspicious, suspected, verdkmmen, v.t. tamp, dam check stunt. Verdampfapparat, m. evaporating apparatus, evaporator vaporizer carburetor, verdampfbar, a. vaporizable volatile. Verdampf-barkeit, /. vaporizability, volatility. 

Fig. 1. Low-temperature distillation or evaporation apparatus. When solids are being collected, the Dewar flask bottom should be as indicated by the broken line.

Fig. 8.1.4 Schematic illustration of the evaporation apparatus with electron beam heating, DP and MBP mean diffusion pump and mechanical booster pump, respectively. (Reprinted from J Cryst Growth, 56 S Iwama et a].. Ultrafine powders of TiN and AIN produced by a reactive gas evaporation technique with electron beam heating, pp 265-269. Copyright 1982, with permission from Elsevier Science )...

Fig. 8.1.6 Schematic illustration of the evaporation apparatus with a microwave plasma reaction zone. (From Ref. 38. Reprinted with permission of the Society of Materials Science Japan.)...

RE Condensation of a metal vapor into a solution of a compound in a rotary evaporator apparatus... 

Vacuum deposition is a well-established technique for making very uniform deposits of non-refractory materials on a backing material. In Figure 19.2, we show a typical simple evaporation apparatus. 

Following our results with diethylsilane and diphenylsilane, we consider the evaluation of diisopropylsilane or di-tert-butylsilane. Diisopropylsilane and di-tert-butylsilane may both be bulky enough that they would allow only one addition however diisopropylsilane (bp 96 °C) has a lower boiling point than di-tert-butylsilane (bp 128 °C) and would be easier to be removed at the end of the reaction by simple evaporation on a rotary evaporation apparatus. Unlike the two previous silanes, diethylsilane and diphenylsilane, diisopropylsilane was not commercially... 

Nitrogen evaporation apparatus (N-Evap Analytical Evaporator Model 111. Organomation Association Inc., Northborough, MA, or equivalent). 

Cast iron is used for sulfonation and nitration vessels, as well as for evaporating apparatus, stopcocks, stirring mechanisms, autoclaves, and all apparatus for handling neutral or alkaline liquids. Still greater use of this valuable and easily cast metal is restricted by its inadequate tensile strength. 

For Dewar flasks, metal evaporation apparatus, and most research apparatus, a vacuum of 10 ° to 10 ° Torr is sufficient this is in the high vacuum range, while 10 ° Torr would be termed ultrahigh vacuum. However, for many routine purposes a utility vacuum or forepump vacuum of about 10 ° Torr will suffice, and for vacuum distillations only a partial vacuum of the order of 1 to 50 Torr is needed. 

The acid volumes were reduced using a CEM micro-vap evaporation apparatus and the remaining reduced liquid made up to mark in a plastic volumetric flask with deionised water. 

Flash evaporation is another techniqne for the deposition of films whose constituents have different vapor pressures. Small quantities of the constituents in the desired ratio are continuously dropped at a predetermined rate from a vibration feeder into a sufficiently heated crucible or boat so that they are evaporated instantly. The temperature must be sufficiently high to evaporate the less volatile material. Figure 2.3 shows the flash-evaporation apparatus used to grow the different layers that compose a microbattery metallic contacts, cathode, electrolyte, lithium anode deposited under vacuum of 10-100 mPa pressure. This system has two vacuum chambers. Vacuum chamber A is devoted to evaporation of In-Se films while lithium and glass films are formed in chamber B. Two interlock mechanisms are used the first one transfers the grown In-Se film to the chamber B and the second interlock system is ntilized to carry lithium pieces from an inert-gas glove box to the evaporation boat. 

Kuderna-Danish evaporator Apparatus for sample concentration, consisting of a small (10 ml) graduated test-tube connected directly beneath a 250 or 500 ml flask. A steam bath provides heat for evaporation with the concentrate collecting in the test-tube. 

Caution Towards the end, the evaporation apparatus must be watched carefully because of foaming (adjust the pressure). 

Fig. 197. Evaporation apparatus for the preparation of hypophosphoric acid, a) Drain b) vaporizer (actually five heating tubes instead of the three shown) h) heating medium h) cooling liquid 1) air intake s, ) ground-glass ball and socket joints y) vacuum connection.

A typical rotary evaporator apparatus is shown in Figure 9.6 and a fractionating distillation apparatus is shown in Figure 9.7. 

The Pu activity is evaporated on a 1 -mil W filament under a heat lamp, but the filament is not flamed. It is then placed in a vacuum evaporating apparatus constructed at this Laboratory. The chamber of the apparatus is evacuated to 5 X 10 4 mm or less of Hg pressure and the filament is heated rapidly several times to about 1300°C to remove readily volatile material. A 1-in, diameter collector plate is then placed in position directly above the sample (1/4 to l/2-in. away) and the filament is heated to 2000°C for a few seconds to violatilize Pu. The Pt disk is then flamed and mounted for fission counting. The yields vary, depending upon the size of the sample being evaporated and also upon the distance between the filament and the disk, but are usually about 40%. By careful control of the W filament temperatures, plates having no visible deposit and checking to within 0.1% are ordinarily obtained. 

The instruments needed for the determination of antimony comprise an atomic absorption spectrometer with electrodeless Sb discharge lamp and potentiometric recorder, a hydride system with quartz cuvette and polypropylene reaction vessel, a pressure decomposition system with a temperature-controlled heating block, and an evaporation apparatus together with various adjustable micropipettes. 

Figure 15.4 Schematic representatiai of evaporation apparatus using an electron-beam heater.

Apparatus Soxhiet extraction apparatus, rotary evaporation apparatus, vacuum dessicator, 1 -L vacuum flask, 1-L round-bottomed evaporative flask, 1-L Erlen-meyer flask, 250-mL Buchner funnel with a coarse fritted disc, etc. 

Hickman Still-Rotary Evaporation Apparatus. A simple microscale rotary evaporator for use in the instructional laboratory consists of a 10-mL round-bottom flask connected to a capped Hickman stOl (side-arm type), which in turn is attached to a water aspirator (with trap) The procedure involves transferring the solution to be concentrated to the preweighed 10-mL flask. The flask is then attached to a Hickman stiH with its top joint sealed with a rubber septum and threaded compression cap. The apparatus is connected by the stiU side arm to the trap-vacuum source with a vacuum hose. lAdth the aspirator on, one shakes the apparatus while warming the flask in the palm of the hand. In this manner, bumping is avoided and evaporation is expedited. The stiU acts as a splash guard. Heat transfer is very effective, and once the flask reaches ambient temperature, the vacuum is released by venting through the trap stopcock. 

With the evaporator apparatus, on the other hand, the propyl acetate showed no acid reaction whatever, and the methyl acetate was only slightly moist. 

When the benzene was in excess, it is certain that the amount of it left in the still-head did not exceed 0 1 gram, and the loss by evaporation was therefore estimated as 0 5 gram in calculating the composition this amount was added to the observed weight of distillate. With methyl alcohol in excess the total loss was greater, but this more viscous liquid does not flow back so completely to the still, and the loss by evaporation was taken to be the same, 0 5 gram. With an evaporator apparatus of five sections the loss by evaporation is usually from 0-3 to 0 5 gram. 

Much time will be saved if an improved still-head is employed for liquids of high boiling point, the pear, and for volatile liquids the evaporator apparatus may be especially recommended. 

A graduate student was using a rotary evaporator to remove solvent from a product. The student attempted to disconnect the round bottom flask from the ground glass joint of the vapor tube of the rotary evaporator but found it was stuck. As pressure and torque was applied the tube broke off just above the male fitting of the vapor tube. The sharp edges remaining on the rotary evaporator apparatus, cut the back of the hand above the thumb and several stitches were required to treat the wound. 

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