NGHIEN ClTU CONG NGHE CHE TAO HQfP KIM HE CHI - THIEC - BISMUT - CADIMI StT DVNG TRONG CHE C H A N XA TRI.
NGO XUAN HUNG, NGUYEN VAN SINH, PHAM DtTC THAI, NGO TRONG HIEP, NGUYEN THE KHANH, VU QUANG CHAT, NGUYEN TRQNG HAI
Vien Cdng nghe Xg hiim 48 Ldng Hg, Hd Ngi
Abstract: Up to now, hospitals in Vietnam have mostly imported radioactii|^
equipments from America, German, France, England to treat cancer. Accompany wifhj those equipments, alloy, namely Cyroben having low melting temperature (<80°C) i?
used to cover patients' good tissues in order to protect them against harmful rays ai^
help radioactive rays get through the cast holes to kill cancer cells. This project^
carried out for determining chemical compositions and melting temperatures S researched alloy to create alloy having low melting temperature (< 80°C) to meW demands for treating cancer in Vietnam.
Key words: Processing flow sheet, name element; lead (Pb); tin (Sn); bismuth (Bi);
cadmium (Cd)
I. DAT VAN DE
Hop kim Cyroben he chi - thie'c - bismut - cadimi (Pb-Sn-Bi-Cd) co nhiet d6 nong cha^
thSp < 80°C dimg trong che chSn xa tri ung thu phai dam bao ba tinh cha't co ban do Ii: '' - Dam bao cac tinh chSt ky thuSt cia nganh VM ly xa tri, che chin tia biic xa dat 92- 95% so vori nguon met khdng che chdn, sao cho cac mo lanh cua ngu6i b6nh nhan chiu mflt ' li6u luong tia biic xa cang tha'p cang tdt.
- Nhiet do nong chay tha'p, di di na'u chay, d6 due theo hinh d^ng phiic tap. —.
- Han che' dflc hai cho nguM gia cong mSu che chSn, cho benh nhan va y bac sy dieu tri. ' j II. KET QUA THUC NGHIEM VA T H A O LUAN
Phan ti'ch thanh phan hoa hoc, do nhiet do ndng chay ciia mSu hop kim nhap khiu, til cac thdng sd nhan duoc nay lam tidn di nghien cilu va tham khao cic tai lieu nu6c ngoai da cong bd de dinh hudng thi nghiem.
TT 1
Bdng 1 .Thanh phdn h od hoc mdu Thanh phan,%
Bi 51,5
Pb 28
Sn 10
Cd 10,32
hc]} kim nhdp khau Nhiet do nong
chay°C 80
Kha nang che chan tia biic xa
95%
Hgi nghi Khoa hgc vd Cdng nghe hgt nhdn todn qudc lan thir IX. Ninh Thudn 18-19/8/2011 359
Bdng 2. Thdnh pbdn hod hgc vd tinh chdt cua mdt so hop kim cd nhiet do ndng chdy thdp
•si^'MS"^
Nhiet do ndng chay: I I T T1 (47°'C)
Mat do: 0.3200pao/in' (Ipao = 450g) 44.7%Bi - 22.6%Pb - 8.3%Sn - 5.3%Cd - 19.1%In
p^^ii^*^^ffl Nhiet do nong chay: 136°F Mat do: 0.3253
pao/in^
?,Bi - 16%Pb - 12%Sn - 2l%In
Nhiet do ndng chay: 158°F
(70°'C) Mat do: 0.3390pao/in'
0%Bi - 26.7%Pb - 13.3%Sn - 10%Cd Siflnap .„.,j_
W^wSM Nhiet dp ndng chay: ISS-WO^F (70-88''C) Mat do: 0.3S41pao/in'
Nhiet dd ndng chay: 203°F (95°C) Mat do: 0.3502pao/in^
i2.5%Bi - 32%Pb - 15.5%Sn
Nhiet dd ndng chay: 217-440°F ( 1 0 3 - , , . , . . „ , „ „ ,.
^ iii--^KaMjTi-70f^\ • Mat do: 0.3660pao/ir
1. Nguyen lieu va thiet hi
- Lo giS'ng nho, dung tich 5kg/me. Nhiet do nung max = lOOO'^C, cd dieu khien nhiet do.
- Cdc, chen nung chiu nhiet, dung tich tit lOOg den 2000g/me, nhiet ke thuy ngan do duoc dfn 500°C, cac khay dung san phim bang thep indc, bang thuy tinh va bSng nhua.
- Cac kd't qua phan tich nguy6n lieu duoc chi ra trong bang 3.
Bdng 3. Thdnh phan nguyen lieu ban ddu
Stt 1 2 3 4 5
Ky hieu m^u
MOI M02 M03 M04 M05
C^c chi tieu phan tich (%) Pb
99,85 99,87
- - -
Sn
_ _
99,94
. -
Bi
_ _ .
99,95
-
Cd
_ , _ _
99,86 Khac
_
_
_
_
-
360 Hdi nghi Khoa hgc vd Cdng nghe hgt nhdn todn qudc lin thi IX, Ninh Thudn 18-19/8/2011^
2. Nghien ciiu qua trinh hop kim hoa cac kim loai thanh phSn he chl-thiec-bismulh- cadmium (Pb-Sn-Bi-Cd)
Thi nghiem l:Thanh phdn phdi lieu 500g hop kim (Pb-Sn-Bi-Cd) lua chpn nhu sau:
Bdng 4: Thdnh phan pligi lieu bgn ddu Nguyen to
Thanh phan % Bi 50
Pb 30
Sn 10
Cd 10
Khac
-
Nau chay h6n bop chi va thig^c trude, khi kim loai dat dfin nhiat dd 270°C hop kim chi thie'c chay bokn toan, nSng nhiat cua 16 iSn 300°C (t6c dd n^ng nhiet trung binh 12''C/phiil) cho tir tir bismuth va cadimi vao, khuSy lien tuc tranh d^ bismuth va cadimi n6i Ifin trSn hi mat kim loai long. Qua trinh tan cua bismuth va cadimi se k^o di^m chay ciia bop kim (Pb-Sn-Bi- Cd) xuong cho ta hop kim co nhiet d6 nong chay tha'p. Khi bismuth \k cadimi tan h^t giii nhiet trong thcri gian 5 phut, khua'y lien tuc dong th6i vdt sach xi. LS'y hop kim 6.6 ra khay in6c sach d^ ngudi ngoai khong khi ta dupe hop kim chi - thiec - bismuth - cadimi.
- Ke't qua thi nghiem; Cat mlu hpp kim nay dem pbSn tich th^nb phSn hod hoc duoc ke't qua nhu sau:
TT 1
Bdng 5: Kit qud phdn tii
Hpp kim P b - S n - B i - C d
h thdnh phdn hod hoc cua I op kim Thanh phan hoa hoc, (%)
Pb 31,6
Sn 9,5
Bi 48,3
.
^^ ll 1
9,2 1
Do ty trong cua hpp kim dong thcfi n^u chay lai d^ kilm tra nhiet d6 nong chay cua hpp kim sir dung nhiet ke" thuy ngan, ke't qua dupe chi ra 6 bang sau:
TT 1
Bang 6: Mdt sdket q
Hpp kim P b - S n - B i - C d
ud kiem tra mdu hap kim Nhiet dp nong chay
hop kim, "C 78
Khoi lupng rieng, g/cm^
9,90
3. Nghien curu anh huinig cua nhiet dp na'u luyen den hieu suit thu hoi va nhiet dp nong chay ciia hop kim (Pb-Sn-Bi-Cd)
Thi nghiem 2.
- Chpn ty 14 phdi lieu gdm: 50%Bi-30%Pb-10%Sn-10%Cd - Thiic hien 03 thi nghiem cd trpng luong bang nhau vk bang 200g.
- Khi kim loai dat nhiet do 270°C, chi va thid'c chay long hoan toan, Nang nhiSt dfii SOO^C cho 50% tdng lupng bismuth va cadmium vao, khu^y lifin tuc, sau 5 phut hpp kim cliay long het, tie'p tuc vdt x! va cho het lupng con lai bismuth vk cadmium vao. Sau 4 phut kim loai chay hoan toan ddng thdi vdt xi va giir nhiet them 5 phiit thi tat Id, la'y san phim ra dd vJo khudn thep indc lam nguoi ngoai khdng khi. Lam lai hai thi nghiem tucfng tii nhimg nSng nhiet dp den 350°C va 400°C khi cho bismuth va cadmium v4o.
Khi san phim ngudi, can lai de ki^m tra hieu suit thu hdi san phim, sau dd nung dl kie'm tra nhiet dp ndng chay cua hpp kim. Ke't qua cac thi nghiSm dupe th^ hidn trong bang
JHgi nghi Khoa hoc vd Cdng nghe hgt nhdn tadn qudc Idn thu IX, Ninh Thudn 18-19/8/2011 361 Bdng 7: Ket qua kiem tra
TT 1 2 3
Hpp kim P b - S n - B i - C d Pb - Sn - Bi - Cd P b - S n - B i - C d
nhiet dd ndng chdy vd hieu sud't thu hoi ciia hap kim Nhiet dd na'u hpp
k i m , °C 300 350 400
Nhiet do ndng chay hpp kim, "C
78 80 85
Hieu suat thu hdi san pham (%)
95 92 90
; Khi nghien cihi cho tha'y nhiet do anh hucmg rat Idn de'n biSu suS't thu bdi san ph£m va ,; nhiet dd nong chay ciia hpp kim. Khi nang nhiet cang cao thi bismuth va cadmium chay hao . cang nhieu, vi hai nguySn td nay co ai luc hoa hpc vdi oxy rS't manh, d nhiet dd cao chiing de j bi oxy boa tao thanh oxit di vao xi, do dd bismuth va cadmium bi ma't di nhieu, din de'n nhiet , dd nong chay ciia bcrp kim tang len. Vi bismuth va cadmium la hai nguyen td tro chay ddng
vai tro quan trpng, quyet dinh nhiet dd nong chay tha'p ciia hpp kim.
J 4. Nghien ciru anh huong cua th5i gian giii' nhiet den nhiet do nong chay cua hpp kim (Pb-Sn-Bl-Cd)
Thi nghiem 3:
- Thanh pbSn phdi lieu gdm: 50%Bi-30%Pb-10%Sn-10%Cd. Na'u chay hoan toan hpp
" kim chi va thiec, tiep tuc cho bismuth va cadmium vao, khuSiy lien tuc, gift nhiet cho 16 ludn . dat 330''C. Di thdi gian giii nhiet la 15 phiit, khdng khua'y dao. Sau 15 phut hop kim tao mot
ldp xi day mau den n6i \tn tren be mat hpp kim, vdt bet lupng xi nay dem can, chie'm 11%
(22gam) tdng trpng luong hpp kim.
Khi vdt sach xi IS^y hop kim 6.6 ra khudn lam ngudi, cSt miu hpp kim nay dem phan tich thanh phdn boa hpc va do nhiet dd ndng chay cua hpp kim dupe ket qua nghi trong bang
TT 1
Bdng 8: Thdnh phdn hod hoc vd nhiet dd ndng t Thdi gian giii
nhiet, phiit 15
Nhiet do ndng chay hpp kim, °C
87
hay cua hap kim Thanh phan hoa hoc, (%) Pb
40,8 Sn 10,3
Bi 41,5
Cd 7,3 Qua thi nghiem cho thay, thcfi gian na'u luyen cung anh hudng den nhiet do ndng chay cua hpp kim. Keo dk\ thdi gian nau luyen kl tfir khi cho bismuth va cadmium vao se chay hao hai nguyen td' nay chu yeu, dSn de'n nhiet dd ndng chay ciia hpp kim bi tang len.
Thi nghiem 4:
TTiuc hien tuong tu thi nghiem 3 khi na'u chay hoan toan hpp kim bdn nguyen, nhung thdi gian giiJ nhiet la 30 phiit, khdng khua'y dao. Sau 30 phiit lupng xi mau dem nhi6u hon chi^m 16% (32gam) t6ng trong lupng hpp kim.
Bdng 9: Ke't qud thdnh phdn hod hgc, nhiet do ndng chdy cua hop kim
TT 1
Thdi gian giii nhiet, phiil
30
Nhiet dp ndng chay hop kim, "C
116
Thanh phan hoa hpc, (%) Pb
41,8 Sn 14,2
Bi 37,7
Cd 6,2
362 Hgi nghi Khga hgc vd Cdng nghe hgt nhdn loan qudc lin thi IX, Ninh Thudn 18-19/8/2011 ' Vdi k^t qua thi nghiem nay cho thiy khdng ndn keo dai thdi gian nlu luyen hpp kim, khi hpp kim da chay long hoan toan. Thdi gian tdt nhit thu dupe hpp kim cd nhiet dd n6ng chay tha'p la 5-7 phiit vdi thi phap cdng nghe khuly lien tuc d^ hpp kim hoa holn toan cfc kim loai thanh phin vdi nhau.
5. Nghien ciiu thur tu phdi lieu qua trinh hpp kim hoa he bdn nguyen (Pb-Sn-Bi-Cd) Thi nehiem 5:
Thuc hien thi nghiem gdm 300g hpp kim (I50gBi, 90gPb, lOgSn, lOgCd), nlu chay bismuth trude sau dd cho thie'c, chi va cadmium vao. Qua trinh nlu chay dupe thuc hien trong ' Id gie'ng khdng cd khi bao ve. Sau thdi gian 26 phiit nhiet dd cua Id dat 290°C thSn thiy toilii bd 150g Bi kim loai chuyen hoa hft thknh oxit bismuth cd mlu nau thim. Vi vay holn loilii khdng th^ nlu chay kim loai bismuth trude, khi nghien cthi hpp kim cd nhiet dd ndng cliay ' thip ma cd mat nguyen td nay.
Thi nehiem 6:
Cung thuc hien thi nghiem gdm 300g hpp kim (150g-Bi, 90g-Pb, lOg-Sn, lOg-Cd), nSi ; chay cadmium trude sau dd cho thie'c, chi va bismuth vao. Qui trinh nlu chay dupe thuc hien trong Id gi^ng khdng cd khi bao ve. Khi nhiet dp cua Id dat 325°C thi cadmium kim loai chay long, nhung mdt phin cadmium da bi chuyen thanh oxit, ndu giO nhiet d 325°C lau hotic nang nhiet cao hcfn thi cadmium se chuyen hoa tir tit cho de'n he't thinh oxit cadmium. Nhu vay v6i thi nghiem 6 cho thiy: khdng ndn nlu chay cadmium trude, hieu suit thu hdi hpp kim thip do cadmium bi chly hao, ham lupng cadmium giam di din d^n nhidt dp ndng chay c6a hpp kim se cao.
6. Cac ket qua phan tich:
Tdng hpp cac k^t qua phan tich dupe thdng ke trong bang sau:
Bdng 10: Ke't qud phdn tich thdnh phdn had hoc cua hop kim
Stt 1 2 3 4 5 6 7 8
Ky hieu mau SPOl SP02 SP03 SP04 SP05 SP06 SP07 SP08
Cac chi tieu phin tich (%) Pb
30,1 31,6 40,8 41,8 35,17 30,28 40,49 39,73
Sn 19,4 9,5 10,3 14,2 5,08 10,49 9,32 5,26
Bi 49,2 48,3 41,5 37,7 49,17 44,53 45,28 39,61
Cd
_
9,2 7,3 6,2 9,27 14,68 4,73 9,71
Khic
. _ . . - t^
- I
- - '
7. Sur dung hpp kim cyroben do dac, kiem tra kha ndng che ch^n tia biic xa tren nguon htc xa cua TT An toan Biirc xa va Moi trudng, Vien Khoa hoc & Ky thu^t Hat nhan
Sir dung 2kg hpp kim m5u thi nghiem 2, co nhiet dd ndng chay 78°C, duoc nJCu chay \^ I diic khudn co dd dky 10mm. MSu hpp kim nay dupe gSn vko mdt gi^ dd la khay plastic trong sudt sau dd dat trude ngu6n biic xa d^ do dac, ki^m tra kha nSng che chan tia biic xa tai Tmng tam an toan biic xa va mdi trudng.
Hdi nghf Khoa hgc vd Cdng nghe hgt nhdn todn qudc lan thu IX. Ninh Thudn 18-•19/8/2011 363
* Do he sd truyen qua cua khay
Do dac Ry,,^ va R^^ trong nude siJr dung khay plastic, trucmg chiau chu^ (10 x 10 cm) Bdng II: He sotr tyen qua ciia khay
He sd truyen qua cua khay TT
1 2 3
Ket qua 95.4%
96.2%
96.2%
R,», 573.3 573.3 556.1
541.3 551.4 535.1 L5n do thii nh^t:
K€t qua trong bang 11 vdi Idn do thii nhift, khi ngudn md hoan loan (R^) khdng che chan gi thi he sd chuyen qua ciia ngudn dat R ^ = 573.3; N^u ta sir dung mdt khay (Ry,ay) bing plastic trong sudt che ngu6n khi dd ba sd chuyen qua cua ngudn la (Ryuiy) = 541,3. nhu vay he sd chuyen qua ciia ngudn giam tit 573,3 xudng con 541,3 \k ka^t qua dat dupe la 95,4%
tia biic xa cua ngudn di qua. Nhu vay khay plastic che chan dupe 4,6% tia biic xa.
Do ISn hai v& ba:
Dupe ti^n h^nh tuong tu nhu Xin do thd nhSit, k^t qua cua ISn hai va ba do dupe 96,2%
' tia biic xa truyen qua. NghTa 1^ khay plastic che chan dupe 3,S%.
* Do ha sd truyen qua cua khdi
^ Rfchay v^ Runy t Hws tTOug Hudc svt diuig khdi vat lidu cyroben, trudng chia^u nho 8 x 8 cm Bdng 12: He sd truyen qua cda khdi
He sd truyen qua cua block TT
1 2 3
Ket qua 6.0%
6.0%
6.0%
'^kha. + khoi
42.82 42.84 42.81
534.6 535.1 535.4 Trong bang 12 la k^t qua do ha sd chuyen qua ciia khdi cyroben. Vdi l^n do thii nh^t khi sii dung khay (Ryiay) bang plastic trong sudt che ngu6n, khi dd he sd chuyen qua cua ngudn Ii (Ruay) = 534,6. Khi six dung khay plastic diing di dd khdi cyroben che chan ngu6n biic xa vdi trudng chiaii nho 8 x 8 cm thi ha sd chuyen qua ciia ngudn chi con 42,82 tuong duong 6,0% ngudn biic xa di qua. Nhu vSy sir dung khdi cyroben vdi khay dd Ik plastic da che -ch^ dupe 94% ngu6n biic xa.
Tuong tu vdi kat qua do I5n hai va 1^ ba hpp kim cyroben d^u che chin dupe 94%
ngu6n biic xa so vdi khi ngudn md ho&n toan.
"'In. KfT QUA VA T H A O L U A N
. - Hpp kim cd thanh ph&i trong khoang (20-30%Pb, 10- 15%Sn, 50-55%Bi, 10- '•12%Cd) cd uu di^m nhlft vi khi hpp kim hoa cho nhiet dd ndng chay thSip va che cbSn dat 94-
"95% ngu6n biic xa so vdi khi d^ ngudn mcr hoan toin khdng che chin gi.
364 Hdi nghj Khoa hoc vd Cdng nghe hgt nhdn todn qudc idn thuIX, Ninh Thudn 18-19/8/2011 - Da dat dupe muc tidu nau ra cua di tai, dd la: n^u dupe hpp kim cd nhiet dd nong chay thap (<80''C), phii hpp vdi yeu cSu eua nganh xa tri.
- Che chin dat 94 - 95% ngu6n biic xa so vdi khi nguon md hokn toan, dam bao cho cac md lanh (ta' bao lanh) khdng bi t6n thuong.
IV. KET LUAN
- Tren co sd nguyan lieu va thiet bi trong nude da nSii luyen 6n dinh hpp kim cd nhiet da ndng chay tha'p < SO^C tuong duong vdi hpp kim nhap ngoai, phuc vu cho nganh y hpc xa tri.
- Chu dpng ngudn nguyan lieu trong nude, khdng phai nhap khiu hpp kim n&y.
TAI LIEU TRICH DAN
[1]. Nguyan Khic Xuong. "Vdt lieu kim logi mdu". Nha xuS't ban Khoa hpc va Ky thuat. Ei Npi - 2003.
[2]. Phiing Vie't Ngu, Pham Kim Dinh, Nguyen Kim Thi^t. Ly thuye't cac qua trinh Luyen kim. Hoa luyen, nha xuat ban Giao due, 11/1997.
[3]. B. N. ARZAMAXOV, ngudi dich: Nguyen Khic Cudng, Dd Minh Nghiep, Chu Thien Trudng, Nguyen Khic Xuong. Vat liau hpc - Nha Xua't ban Giao due, 2000.
[4]. Crystal Structure of phases of binary alloy Systems, compiled by Donald. T. Hawkisc information scientist, bell laboratories, miirray hill, N.J.
[5]. Pro. Y. LAKHTIN, ENGINEERING PHYSICAL METALLURGY, translated from the Russian alloy Nicholas Weinstein, MIR PUBLISHERS, MOSCOW. 1968
[6]. D.A. Porter Rautaruukki Oy Research Centre Raahe Finland, Phase transformations in Metals and alloys, second edition. London-Glasgow-New York-Tokyo-Melboume- Madras.
