B,LIHL-

REPORT No: NMLIMST/IAF/1.13/64/2005

July, 2005

~"

~.. Investigation on the Residue of Fuel System of MIG 21Bison Aircrafts~

Sponsored by

40 WingAir Force

C/O 56 APO

I ~I

~.,~~~

Materials Science & Technology Division

National Metallurgical Laboratory

(Council of Scientific and Industrial Research)

Jamshedpur - 831007--- -------

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NATONAL METALLURGICAL LABORATORY, JAMSIIEDI>URInvestigation on the Residue of Fuel System of MIG 21 Bison Aircrafts

REPORT No: NMLlMST/IAF/I.13/64/200S, July 2005.

i:

2

NATIONAL METALLURGICAL LABORATORY(Council of Scientific & Industrial Research)

......'" JAMSHEDPUR

PROJECT COMPLETION REPORT

Project Title: Investigation on the Residue Project No. :of Fuel System of MIG 21 Bison Aircrafts

(ReportNo.:NML/MST /IAF/l.13/64/2005)

Date of Project Initiation: 04.07.2005

Date of Completion: 08.07.2005

Project Team Members : Class:

Mr. S.K. Das (PL) Public document (Free/Priced)Dr. S.R. Singh (Co-PL) Restricted circulation (X)

Only to clientSecret

Customer / Client's name and address: Classification:

FIt Lt. P. Pathak In-house

Fit Cdr MCC Fit Grant-in-aid

For AOC Sponsored (X)

40 Wing, AF, C/O 56 APO Consultancy

TEL: (0751 )2470775/4404Collaborative

Date of Report: 08.07.2004

Area: Material Characterisation. Specify Type:

Sub Area: Microstructural Analysis.Ongoing Area: (X)New Area Initiated:

Key Words: Mig-21 aircraft, abrasive wear, Al alloy, mineral-contamination, tin dendrite, fuel system.residue.

Abstract: The suspected cases of contamination of fuel in the ten MIG 21 Bison aircrafts collected fromaircraft fuel system are investigated. Residue collected from all the 10 aircraft's fuel system has flattenedaluminium particles as a major constituent of the residue, amounting to 70-80%, o[ total residue in eachaircraft. The maximum size of these particles is - 100 !illl. These particles are derived from componentsmade o[ AI-Mg alloy. The flattened morphology of Al particles and abrasion makes on the flat [acesindicates that the particles are generated because of contact abrasive wear in the system. Moreover, themorphology of some of the particles is similar to that of machined chips, which might have formed duringinitial stage of abrasion when the tolerances between contacts are tight. Rest of the balance (20-30%) residueconsists of mineral particles of varying composition and maximum size of -25 !illl. This may be ofextraneous origin, such as rock/mineral/sand. Few isolated dendrites of tin arc found in the residue of 4aircraft's fuel system. Tin has a melting point of 232° C and these dendrites are fom1ed during solidificationof tin. This might have fom1cdduring tinning of surfaces of components in the system.

Details of IPRs (PI tick): NA If no IPR taken, reasons: NA

Patent

CopyrightTrade Marks

Report Issuance Authority: Dr. S. R. Singh Signature: "S.,. 5

NATONAL METALLURGICALLABORATORY, JAMSIJEDJ>URInvestigation on the Residue of Fuel System of MIG 21 Bison Aircrafts

REPORT No: NMUMST/IAF/1.13/64/200S, July 2005.

BACKGROUND

There were cases of suspected contamination of fuel at the operating base of MIG 21 Bison

aircrafts. The residue was collected from the fuel system of ten such aircrafts. The residue of

the fuel system showed the presence of shining and dull grey particles. The filtered samples

collected on Millipore paper were received at NML, Jamshedpur, from 40 Wing, AF on 4th

July 2005. The investigation was assigned to NML vide Letter No. 40W/S.820/2/l/Eng dated

28thJune 2005 from 40 Wing, AF.

SCOPE OF WORK

Based on the requirements of the 40 Wing, AF, it was decided to do the following:

1. Visual examination, identification and samples preparation for microstructural analysis.

2. SEM morphological studies of residue particles.

3. Microanalysis of residue particles by SEM-EDS

4. To find out the type of materials and possibly the origin which causes the contamination

of the fuel.

EXPERIMENT AL RESULTS

Visual Examination, Sample Preparation, & Identification

All the residue samples collected from the fuel system of ten MIG 21 Bison aircrafts arc

listed in the following table. Samples are prepared by sprinkling the collectcd residue on

double-sided carbon tape mounted on brass stubs for microstructural and microanalysis in

SEM-EDS. The overall appearance of residues is collated in the Table -1.

Microstructural Studies

The microstructural features are observed in JEOL 840 A scanning electron mlcroscopc

(SEM). This reveals the morphology and distribution of constituent particles in thc residuc

ii'om each aircraft. The compositional analyses of representative particle arc also analysed by

K.evcx energy dispersive spectrometer (EDS). The summary of these observations is collatcd

in the Table I whereas microstructural and microanalysis data are illustrated in Appendix-I

(Fig. I to Fig. 10). In general, residue tTom each aircraft consists of dark platesltlakcs and

:I

1IT""

NATONAL METALLURGICAL LABORATORY, JAMSIIEDPURInvestigation on the Residue of Fuel System of MIG 21 Bison Aircrafts

REPORT No: NMLIMSTIIAF/1.13/6412005, July 2005.

white charging particles. The charging of white particles under electron beam indicates that

they are non-conducting material which may be derived from rock/sand/mineral and therefore

of extraneous origin. The contrast of these two classes of particles is reversed in SEM

micrographs as compared to visual appearance. The EOS microanalysis of plate/flake

indicated Al as major element and Mg as minor element. The Mg peak in the EOS spectra

appear as small hump on the left side of the AIKa peak. The spectra of AI-particles from all

the aircrafts have similar nature. Therefore, these plates/flakes are derived Irom the same AI-

Mg alloy. Moreover, the surfaces of Al particles are decorated with abrasive wear marks.

This indicated that these Al particles are generated by abrasion of a component made of AI-

Mg alloy in the fuel system. EOS microanalysis of white charging particles shows presence

of elements, usually found in minerallrock/sand. These particles have different composition

indicating presence of different mineral phases. The maximum size of Al platelets and

mineral particles are -100 !lm and -25 !lm respectively. The residue from each aircraft

contains about 70-80% of Al particles and rest constitutes the mineral particles. In addition

few dendrites of Sn have been observed in the residue of four aircrafts. The dendrites are

usually formed because of solidification of molten metal.

Table 1. Sample identification, visual appearance and summary of SEM-EDS studies.

4

Sample No. Visual appearance Summary of SEM-EOS studies

1. Major Al particles with Iitt!e MgA/C No. CU-2079 Mainly shining (abraded & machined).

2. Si, Mg, AI, S, Fe containing complexmineral particles (White particles in SEMmicrograph).

1. Major Al particles with little MgA/C No. CU-2119 -00- (abraded & machined).

2. CI, S, Ca, AI, K, Na, Si, P Cu & Zncontaining complex mineral particles, Si,Al & K rich mineral particles and

complex porous particles (White particlesin SEM micrograph).

3. Sn dendrites1. Major Al particles with little Mg

A/C No. CU-2l64 -00- (abraded & machined).2. Alumina particles and complex mineral

particles of ditTerent composition(Whiteparticles in SEM micrograph).

NATONAL METALLURGICAL LABORATORY, JAMSIIEDI'URInvestigation on the Residue of Fuel System of MIG 21 Bison Aircrafts

REPORT No: NMLIMSTIIAF/1.13/64/2005, July 2005.

A/C No. CU-2258

AlC No. CU-2307

.. ~,' .

AlC No. CU-2771

A/C No. CU-2772

A/C No. CU-2773

A/C No. CU-2795

A/C No. CU-281 0

-Do-

Dark grey with

some shining

particles

Mainly Dark grey

(dull) with some

shining particles

Mainly shining

-Do-

Mainly shining

Dark grey with

some shining

particles

1. Major. AI. particles with little Mg(abraded & machined).

2. Ca, Si, CI, AI, Mg containing complexmineral particles (White particles in SEMmicrograph).

3. Sn dendrites.

1. Mainly Al particles with little Mg.2. Si, Mg, AI, S, CI, Fe, K & Ca containing

complex mineral particles, iron oxide,complex mineral particles of varyingcomposition (White particles in SEMmicrograph).

1. Mainly Al particles with little Mg.2. Si & Mg rich mineral, iron oxide,

complex mineral particles of varyingcomposition (White particles in SEMmicrograph).

3. Isolated dendrites of Sn.

4. Cd rich particle.1. Major Al particles with little Mg

(abraded & machined).2. AI, Fe & Si containing complex mineral

particles (White particles in SEMmicrograph).

3. Sn dendrites.

I. Major AI particles with little Mg(abraded & machined). .

2. Calcium silicate particles, Aluminaparticles and Si, AI, Ca, Na containingcomplex mineral particles (Whiteparticles in SEM micrograph).

I. Major Al particles with little Mg.2. Alumina & S, AI, Ca, Si & Cu containing

complex mineral particles (Whiteparticles in SEM micrograph).

1.' Major Al partiCles with little Mg.2. Silica particles (angular shape).3. Si, Mg, Fe containing complex mineral

particles (White particles in SEMmicrograph).

4. AI, Mg, Ca, K, Fe & Si containingcomplex mineral particles (Whiteparticles in SEM micrograph).

5. Fragmented complex particles containingZn & Cl.

5

NATONAL METALLURGICAL LABORATORY, JAMSIIEOPURInvestigation on the Residue of Fuel System of MIG 21 Bison Aircrafts

REPORT No: NMLIMST/IAF/1.13/641100S, July 2005.

CONCLUSIONS

1. Residue collected from all the 10 aircraft's fuel system has flattened aluminium particles

as a major constituent of the residue, amounting to 70-80% of total residue in each

aircraft. The maximum size of these particles is - 100 /lm.

2. The Al partic1es in all the aircraft are derived fTomcomponents made of AI-Mg alloy. The

flattened morphology of Al particles and abrasion makes on the ~at faces indicates that

the particles are generated because of contact abrasive wear in the',system. Moreover, the

morphology of'some of the partic1es is similar to that of machiI)ed chips, which might

have formed during initial stage of abrasion when the tolerances between contacts are

tight.

3. Rest of the balance (20-30%) residue consists of mineral particles of varying composition

and maximum size of -25 /lm. This may be of extraneous origin, such as

rock/mi neral/ sand.

4. Few isolated dendrites of tin are found in the residue of 4 aircraft's fuel system. Tin has a

melting point of 2320 C and these dendrites are formed during solidification of tin. This

might have formed during tinning of surfaces of components in the system.**********

6

APPENDIX-l

iFigure Ia. SEM micrograph of sample CU-2079 showing morphology of residue. Dark flattened particles is AI-Mg alloy

(Fig. Ib) and bright/white particles are complex mineral (see the corresponding EDS spectrum in Fig. Ic).

- " Alf< 0 uu-u -

1500

1000.

500

0b ..;' keV, .. -; , , ! " I

Figure lb. EDS spl:ctrum of dark flattened particles (sample CU-2079) showing major p~ak of Al & minor hump due toMg.

FeKIt

i ~'SI~~~"""",,, ~,!,;,.J(I\ . koV0 r-- , , , . , . , , , 1 ~-

!-'igure Ic. EDS spectrum of a~rightJwhite particle (sampIe5CU-2079) showing Si, Mg. ~l, S 8.: Fe containing complexmineral particle.

7

S,K "600

500

400AIK",

300

200 MaK'

100 '"'' , S K "

Figure 2a. SEM micrograph of sample CU-211~showing morphology of residue. Dark flattened particles are AI-Mgalloy (Fig. 2b) and bright/white particles are complex mineral and grey dendrites of Sn (marked). The corresponding EOS

spectra are shown in Fig. 2c, 2d, & 2e).

J-_~n--....

12000"":

AIKa

I

I-1

1500J,

.,i

1000-'

5OO-i

0 /' , keV

b ,1 $ 1'0

Figure 2b. EOS spectrum of dark flattened particle (sample CU-2119) showing major peak of AI & minor hump due It>Mg.

200 --1

---CIK <>

S K M.

150

CaK.,

100AIK a

50 II,

KK

I

C I I~' CIIi..if.IJ ZnK "CaL 1\ S K IlJl ~ CuK IICaL, 1L 1\ P K II K K I' ;

SiK II . ". koV

Figure 2c. EDS spectru~n ~f a br~ght/w~ite p~rticlc ~sampie CU-~ 119) 'of con~plcx l1lincn~fcontaining CI, S, <-:'a,AI, K.Na, Si, P, Cu & Zn.

Ii

900

800.SiKa:

700 -

600

500 AI

40'

300KKa

200

100

0keY

10

Figure 2d. EDS spectrum of another bright/white particle (sample CU-2119) showing Si rich mineral particle.

11001

10001

9001

SnLa

800

700

600

500-

400-=L0

30. -

200

100- i01' -r- ~,;-_.~,_.~---;-~,~kev

0 5 10

Figure 2e. EDS spectrum of grey dendrite particle (sample CU-2119) of Sn

9

Figure 3a. SEM micrograph of sample CU-2164 showing morphology of residue. Dark flattened particles are AI-Mgalloy (Fig. 3b) and bright/white particles are complex mineral and alumina (see the corresponding EDS spectrum in Fig.

3c, 3d, & 3e).

,~rI1

'~l

iAIK"

1500

1000

,~j

500-~

~

010

keV

10

Figure 3b. EDS spectrum of dark flattened particles (sample CU-2164) showing presence of Al & Mg.

10

AIKa300

Mg

200 IKaS Ka

CaKx

5(1

keY" , , '--r

Figure 3c, EDS spectrum ofa bright/white particle (sample CU-2164) showing Al r1h complex mineral particle

K Ka

FeKa

T'-'~-5

keY,10

Figure 3d. EDS spectrum of another bright/white particle (sample CU-2IM) showing Si rich complex mineral particle.

l600

AIKa

500-Mg~

400-=

iKa

300-

200-='

100-

LK keY

s 10

Figure 3c. EDS spectrum of a bright/white particle (sample CU-2164) showing alumina rich particle.

IIr~;;~'-;!-'-'~!\ \ \ ',. ; '.: " '-" ,.;; c- !

',".! dO'OsCl) , \, <;,<Y""<.-

J\_:~ .,,: ,ex u~:> " .

500 . SiKa

400

AI

0-Fe

4(a) 4(b)

Figure 4a. SEM micrograph of sample CU-2258 showing morphology of residue. Dark flattened particles are AI-Mgalloy (Fig. 4c) and bright/white particles are complex mineral (see the cOITesponding EDS spectrum in Fig. 4d &4e). Fig.

4b: higher magnification SEM micrograph revealing dendrite morphology of Sn.

AIKu

1500

1000-

500-

~ keY

10

Figure 4c. EDS spectrum of dark flallened particle (sample CU-2258) showing presence of Al & Mg.

12

~i~r4J" II'--~~-;;;:,"'"'~~~:~~S:-~;::-"._':-",. : " "."

'"'-"'-"""''''

~~ ~.,<..~

"......-~.

CaKx

SiKa:. CIKa:

1'0

keY

Figure 4d. EDS spectrum of a bright/white particle (sample CU-2258) showing Ca, Si, CI, AI & Mg containing complexmineral particle.

AIKa:

200

Mg

iK"

15

100

50CIKa.

SKtx KKa.

0 I10

keV

Figure 4e. EDS spectrum of a bright/white particle (sample CU-2258) showing AI rich complex mineral particle.

I J

Figure 5a. SEM micrograph of sample CU-2307 showing morphology of residue. Dark flattened particles are Al-Mgalloy (Fig. 5b) and bright/white particles are complex mineral (see the cOlTesponding EDS spectrum in Fig. 5c ).

140"AIKa

1300

1200

1100

1000

900

800

100

600

500

400

300

200

450I

SiKa

1iIIi

400

350

300

250

200

150

100 -

~.v

50-

10

Figure 5c. EDS spectrum of a bright/white particle (sample CU-2307) showing Si, Mg, AI. S. CI, Fe, K & Ca containingcomplex mineral partil;le.

14

Figure 5a. SEM micrograph of sample CU-2307 showing morphology of residue. Dark flattened particles are Al-Mgalloy (Fig. 5b) and bright/white particles are complex mineral (see the corresponding EDS spectrum in Fig. 5c).

140nAIKa

1300

1200.

1100

1000-.

900~

800

700..

600

500.c

400..

300

2001100 .~

o~..-l ',. ''!' . S 10 keYFigure 5b. EDS spectrum of dark flattened particle (sample CU-2307) showing presence of Al & Mg.

450.I

SiKa

~~--II

I400

350.

300

250 .

200

150.

100

keV

50..

10

Figure 5c. EDS spectrum of a bright/whitc particle (sample CU.2307) showing Si, Mg, AI. S. Cl, Fe, K & Ca containingcomplex mineral partil;le.

14

".,

"N¥

6(a) 6(b)

Figure 6a. SEM micrograph of sample CU-277 I showing morphology of residue. Dark flattened particles are Al (Fig. 6c)and bright/white particles are complex mineral (see the corresponding EDS spectrum in Fig. 6d ,6e). Fig. 6b: higher

magnification SEM micrograph of dendrites of Sn metal (EDS spectrum in Fig. 6{).

AIKa1

2000

1500~

1000-

500-

~~ keYI

10T

Figure 6c. EDS spectrum of dark flattened particle (sample CU-2771) showing presence of AI-Mg.

15

45(} $ Ka

4(}(}

CdLa

3(}(}

250

100C u 1<0.

150

5(}

Figure 6d. EDS spe~-:t::::i~' bright/white particle' ~s~~~~~~~ho~,"'~~t~J~:, & Cl rich particle.

0 1 y' w>~ Lu ~.. ,A , i keV5 10

Figure 6e. EDS spectrum of a bright/white particle (sample CU-277 I ) showing presence of Sl & Mg.

1100

800

100

900

700

600

500

LfJ400 .

300

200.c.

100 -

0 c~~. ~-, ,. m F '--r-:;:=~:!',"-'--~-,-"-",,,: +' J {:keV

Figure 6f. EDS spectrum of Sn dendrite particle (sample CU-2771.

16

600-j Si,Ka

500-

400 -

300

200'M:;JK

100-

7(a) 7(b)Figure 7a. SEM micrograph of sample CU-2772 showing morphology of residue. Dark flattened particles is Al-Mg alloy(Fig. 7c) and bright/white particles are complex mineral (see the corresponding EDS spectrum in Fig. 7d). Fig. 6b: higher

magnification SEM micrograph of dendrites of Sn (EDS spectrum in Fig. 7e).

~~---1

j AIKa

1500

1000

500

I keY

10

Figure7c. EDS spectrum of a dark flattened particle (sample CU-2772) showing presence of Al & Mg.

17

AIKa

IKa

keY1'0

Figure 7d. EDS spectrum of a bright/white particle (sample CU-2772) showing AI, Fe & Si containing mineral.

100 SnLa

600

500.

400

300 LB

10

keVI

10

Figure 7e. EDS spectrum of Sn dendrite particle (sample CU-2772).

I X

Figure 8a. SEM micrograph of sample CU-2773 showing the morphology of residue. Dark flattened particles are Al-Mgalloy and bright/white particles are complex mineral (see the corresponding EDS spectrum in Fig. 8b & 8c ).

800

SiKa

700

6CO

500

AI

400

300

200

100 CaKt

keY

10

Figure 8b. EDS spectrum of a bright/white particle (sample CU-2773) showing Si. AI. Ca & Na containing mineralparticle.

400

a6C0

300

200

100

0 -keV

10

Figure Xc. EDS spectrum ofa bright/white particle (sample CU-2773) showing Ca rich particle.

19

II-!!!!

Figure 9a. SEM micrograph of sample CU-2795 showing morphology of residue. Dark flattened particles are Al-Mgalloy (Fig.9c) and bright/white particles are complex mineral (see the corresponding EDS spectrum in Fig. 9b).

100 S Ka

90

80

70AIK"

60

CaKa50

',K"40

30

20 I

I

IkeY

I10

Figure 9b. EDS spectrum of a bright/white particle (sample CU-2795) showing presence of S, AI, Ca, Si & Cu containingcomplex mineral particle.

-~ l

I

keV

10

Figure9c. EDS spectrum of dark flattcncd particle (sample CU-2795) showing presencc of AI & Mg.20

AIKaI

600--:

500--:

400--:

300"':

200-=

lOO

--T

..}

10(a) 10(b)Figure lOa. SEM micrograph of sample CU-281 0 showing the morphology ofresidue. Dark flatten particles are Al (F ig.IOc) and bright/white particles are complex mineral (see the corresponding EDS spectrum in Fig. 10d). Fig. lOb: higher

magnification SEM micrograph of surface of Al particle showing abrasive wear marks.

AIKaaoo

7oo~

600

500

400e

JOo--

200

100

0-1 ..I \ -" IkeY, "; " 1'0

Figure IOC.EDS spectrum of dark flattened particle (sample CU-281 0) showing presence of Al & Mg.

7

Caki,

,_-~_.nr--," "-1 1'0

Figure 10d. EDS spectrum of a bright/white particle (sample CU-281 0) showing AI, Mg, Ca, K, Fc & Si containingcomplex mineral particle.

KK~\ FeKa

keV

21

aoo-:

700-:

600-:

AI

M9j300c

200.-

100 :