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98TABLES 78-S4.-EMISSIVITTES OF A NUAIBER OF M AT E R I A L S

TA B L E 78.-NORMAL SPECTRAL EMl SSl Vl Tl ES FOR SOME E L E M E N T SA N D A L L O Y S

The emissivity, spectral or total. of any non-hlackbody shows the relation between theintensity of its radiation and thatof the blackbody when both ar e a t the sam e temperature.Spectral emissivities have been measuredfor a number of materials for different tempera-tures and different wavelength intervals and are shown in Part1.

Par t 1.-At temp eratur es generall y above 1000 O K

Room temperature values are given n a few instances where they, along with values athigher temperatures, forma connected series and where the values givenfor the h ighe r.temperatures depend on those given for low temperatures.

Te m p y a t u r e

Material KCarbon 1600

2500

1500

Iron 1000

Konal 1200Molybdenum . . . . 300

130020002750

1480-1500

Nickel .......... 1200-1650

Ta n ta lu m . . . . . . . 300140021002800

Emissivi ty

Red Green

in c x X in eA.66 3 9.66 .84

.66 .lo5

.66 .120

.66 ,15066 .I40

.66 .I3

l ue Remarks

in p e x

SolidSolidLiquidLiquidLiquid

.66 .27

.65 .37

.665 .43

.665 .420.665 ,378,665 .353.665 .332

.665 ,375 .535 .425

.665 ,493

.665 .442,665 .415.665 .390

.467 .425

.467 .395

.467 .380

.467 .365

,460 .450

.467 .565

.467 .505

.467 .460

.467 ...

SolidSolid and liquid

Solid

Worthing, A G., Temperature radiation emissivit ies and em ittances, Temperature, Its Measure-ment and Control, p. 1184, Reinhold Publishing Co., 1941.

Pa r t 2.-Emissivity o f a number o f metal s a t t he i r me l t i ng po in t s

(CA expressed in percent)

x = 5 5

Beryllium . . . . . 61 81Chromium . . . . . 53Cobalt . . . . . . . . . . . .Copper . . . . . . . . 38 36Erbium . . . . . . . . . 30Gold

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100

T A B L E 7 9.-C O RR EC T IO N S I N C T O A D D T O B R I G H T N E S S T E M P E R A T U R ER E A D I N G S , F O R D I F F E R E N T E M I S S I V I T Y, T O O B T A I N T H E

T R U E T E M P E R A T U R E concluded)

Em+SlVltY

.10.20

.30

.40so

.60

.7n. .

.80

.85

.90

.95

Pyrometer using red light, wavelength, X = 6 6 5 ~ . nd r l .= 1 4 3 8 0 ~ K at olisrrvecltemperatures degrees tielvin, o

1900 2000 2200 2400 2 6 0 0 2800 3000 3 6 0 0

481.9 541.2 673.0 823.9 995.2 1189.5 1408.3 2237.8312.9 349.8 430.7 521.9 623.8 737.2 862.5 1317.6224.8 250.6 307.0 370.1 440.0 517.2 601.6 902.4166.3 185.2 226.1 271.7 330.4 377.0 436.9 648.0123.2 137.0 166.9 200.0 236.4 276.1 319.2 469.689.3 99.2 120.6 144.2 170.1 198.3 228.9 334.661.5 68.2 82.8 98.9 116.5 135.6 156.2 227.238.0 42.1 51.1 60.9 71.6 83.3 95.9 138.927.5 30.5 37.0 44.1 51.8 60.2 69.2 100.117.7 19.7 23.8 28.4 33.3 38.7 44.5 64.28.6 9.5 11 5 13.7 16.1 18.7 21.5 31.0

TA B L E 8 0 . - C O M P U TAT I O N O F T O T A L E M l S S l V l T Y VA L U E S F O R VA R IO U SG L A S S S A M P L E S A T L O W T E M P E R A T U R E S Iyl

A ppr fn t .emissivtty Computed Temperature Coyre5ted

Thick- transmittance t differential t emlsslvltynew 200 ;ZO t o 0

Sample ( m m ) c c c GVused quartz ..... 1 .9 6 .7 8 .SO .75 ,266 , 1 3 4 , 0 2 3 19 8 1 . 6 7 . 7 6 ,775Corex D . . . . . . . . . 3.40 .SO .80 . 7 6 . I13 .041 002 49 18 2 .91 .90 .83Nonex ........... 1.57 .82 .82 . 7 8 .I45 ,041 .004 31 12 1 .5 .X2 .87 3 3 5

Dissipating of e n e rg y b y l a m p b ulb s.- Th e b ulbof a 120-volt 500-watt lamp dissi-pates 18.5 percent of the input energy to the lamp. About 10 percent is lost by radiationand 8.5 percent by conduction and convection by the surroun ding air. T he losses from o thersimilar lamp bulbs probably agree with this.

%Barnes , B . T., Forsythe, W . E. , , and Ad ams , E . Q . Journ. Opt. SOC. Amer., vol. 3 7 , p. 804, 1947.Assuming no radlatton transmltted through sample from heater and no temperature gradtent.

t Assuming all o f sample at heater temperature. Between front and back surfaces.

T A B L E 8 1. -R EL AT IV E E M l S S l V l T l E S F O R T Q T A L R A D I A T I O N

Emissive power of blackbody= 1. Receiving surface platinum black at25C; oxidizeda t 600 + C.

Temperature, C

' 200 400 600

Silver ........................................ .020 .030Pla t inum (1) ................................. .060 .086

- 110xidized zinc .................................Oxidized aluminum ............................Calorized copper, oxidized......................Cast iron .....................................Oxidized nickel ...............................Oxidized monel ...............................Calorized steel; oxidized........................Oxidized copper ..............................Oxidized brass ................................Oxidized lead .................................Oxidized cast iron.............................Oxidized steel ................................

.113 .153

.180 .185

.210369 .424.411 .439521 547.568 .568.610 .600.631.643 .710.790 .788

.038

.110

.192

.190

-

.478

.463

.570

.568

.589

.777

.787

For radiation properties of bodies at temperaturesso low that the radiations of wave-length greater than 2Op o r thereabouts a re important, doub t must exist becauseof thepossible and perha ps probable lack of blacknessof the receiving body to radiations of those

wavelengths or greate r. F o r instance, see Tab les568 and 573 for the transparency of soot.SMIT HMN IA N PHYSICAL TABLES

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101T A B L E 82.-TO TA L E M l S S l V l T Y VA L U E S O F VA R IO U S M A T E R I A L S A T

L O W T E M P E R A T U R E S *

MaterialAlleghany alloy No. 66 . . . .Alleghany metal . . .Aluminum .

..

Aluminum ....................Aluminum . . .. . . .Aluminum paint . . . .Brass . . .

Chromium . . .

Iron .........................I ron . . . .Lamp black . . . . .Molybdenum . . .Nickel . .Nickel-silver . . .Rad iator paint, black . . . . .Radiator paint, bronzeRadiator paint, cream . .Radiator paint, white . .Silver . . . . .Stainless steel . . . .Steel . . .Tin . . . . . . . .

Zinc

Condition At 100C 320'C 500C

Polished . l lNo. 4 polish .13Commercial sheet .09Polish .095Rough polish .18

. . . . . .PolishedRough plateRough platePolishedPolishedPolishedDark g ray su rfaceRoughly polishedRough deposit

PolishedPolishedPolished

. . . . . .

. . . . . .PolishedPolishedPolishedPolishedComm ercial coatPolished coatCommercial coat

.29,059.77.76.075.052,059.31.27.84

,071.072.135.84.51.77.79.052,074.066.06Y.084.066.21

.77

.75.72.71

.78

For reference, see footnote 38, p. 100.

T A B L E 8 3. -P E R C E N T A G E E M l S S l V l T l E S O F M E T A L S A N D OXIDES

True temperature C 500 600 700 800 906 1000 1100 120060 Fe 0 . 4 0 Fe z O z To ta l 85 85 86 87 87 88 88 89= Fe heatedin air . . . . . . . . . A = .65p - - 98 97 95 93 92

N i O . . . . . . . . . . . . . . . o ta l - 54 62 68 72 75 81 86. . . . . . . . . . . . . . = .65p - 98 96 94 92 88 87Pla t inum :

True temp. ZC . . . 0 100 200 300 400 500 750 1000 1200 1400 1600 1700App.* temp. C . . . - - - 486 630 780 930 1005Total emiss. Pt.. 3 1 4.0 5.1 6.1 7.0 8.0 10.3 12.4 14.0 15.5 16.9 17.5

Splid ...... . . . 89 77 63 52 57 61 37 71 69 60 30Liquid . . . . . . . . 68 63 53 47 51 69 . . 31

Oxides : = 65p N iO Co:tO, Fe:%O, Mm0. TiO r T h O s Y?Os B e 0 K h O x Vp0s C r2 0 s 1 - 3 0 s

. s observed wi t h total radiation pyrometer sighted o n the platinum.T A B L E 84a-TOTA L R A D I A T I O N F R O M B A R E A N D S O O T-C O V E R E D N I C K E L sa

watts/cm2)

K 400 500 600 700 800 900 1000 1-700 1400Soot-covered Ni . . . . . . . ,096 .28 .59 1.87 3 3 4.8Poli:hed in itia l he a t. ,0092 .032 .079 .166 .31 .55 .91 2.ij 4.49

a f t e r above . . .0066 .023 .058 .123 .24 .44 .76 2.04 4.49

saBarnes , Phys . Rev. , vol. 34, p.

1026, 1929.

SMITHSONIAN PHYSICAL TABLES